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3 years ago

9

11. What is the mass of 30,000 molecules? Express your answer in scientific notation. Mass of one molecule of oxygen = 5.3 x 10-

23 gram

2 answers:

GrogVix [38]3 years ago

7 0

Answer:

uhhm I think it is 1.59*10^-18

Step-by-step explanation:

oksian1 [2.3K]3 years ago

4 0

Answer:

1.59*10^-18

Step-by-step explanation:

if not sorry

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Which expression is equivalent to 6x+7-12*2-(3 to the power 2 +3)-x

kow [346]

Step-by-step explanation:

Questions about equivalent expressions usually feature both simple expressions and complex expressions. To check which complex expression is equivalent to the simple expression:

Distribute any coefficients: a(bx\pm c)=abx\pm aca(bx±c)=abx±aca, left parenthesis, b, x, plus minus, c, right parenthesis, equals, a, b, x, plus minus, a, c.

Combine any like terms on each side of the equation: xxx-terms with xxx-terms and constants with constants.

Arrange the terms in the same order, usually xxx-term before constants.

If all of the terms in the two expressions are identical, then the two expressions are equivalent.

Example

How do we solve for unknown coefficients?

Some questions will present us with an equation with algebraic expressions on both sides. On one side, there will be an unknown coeffient, and the question will ask us to find its value.

For the equation to be true for all values of the variable, the two expressions on each side of the equation must be equivalent. For example, if ax+b=cx+dax+b=cx+da, x, plus, b, equals, c, x, plus, d for all values of xxx, then:

aaa must equal ccc.

bbb must equal ddd.

To find the value of unknown coefficients:

Distribute any coefficients on each side of the equation.

Combine any like terms on each side of the equation.

Set the coefficients on each side of the equation equal to each other.

Solve for the unknown coefficient.

Example

How do we rearrange formulas?

Formulas are equations that contain 222 or more variables; they describe relationships and help us solve problems in geometry, physics, etc.

Since a formula contains multiple variables, sometimes we're interested in writing a specific variable in terms of the others. For example, the formula for the area, AAA, for a rectangle with length lll and width www is A=lwA=lwA, equals, l, w. It's easy to calculate AAA using the formula if we know lll and www. However, if we know AAA and www and want to calculate lll, the formula that best helps us with that is an equation in which lll is in terms of AAA and www, or l=\dfrac{A}{w}l=

w

A

l, equals, start fraction, A, divided by, w, end fraction.

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7 0

3 years ago

Read 2 more answers

Explain the difference between an equation and an inequality. Write at least two of each, one of the form px+q and one of the fo

Triss [41]

Answer: One important difference between an equation and an inequality is that if you subtract one side of an equation from the other, you will get 0

In the case of an inequality, if you subtract one side from the other, you will get something other than 0

That’s an important fact about equations and inequalities that is often utilized in finding solutions.

When I was teaching I noticed that students frequently interpreted the =

sign to mean ‘find the answer’. It does not mean that. It only means that the expression on the left hand side has the same value as the expression on the right hand side.

Students who think that =

means ‘find the answer’ become confused when they see symbols like < , ≠

, or ≈

A further issue these days has to do with computational technology.

This issue has to do with variable assignment. In many programming languages, a statement like =+1x1

has the meaning, “Add one to the current value of x

and then reassign that value to x

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has no solution in traditional algebra.

Programming languages that use =

for variable assignment tend to use ==

to mean equality in our traditional math sense.

Though something like the meaning of =

might seem trivial and ‘obvious’ to many people, there’s actually a lot of subtle variations of understanding possible, and it is important to be aware of these nuances, because that is where confusions arise for students.

7 0

3 years ago

Solve the equation <br> -4+-1+2+.....+x=437

aliina [53]

[2<span>] </span>x<span>. </span><span>437 is the answer

</span>

7 0

3 years ago

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Unit 7 polygons & quadrilaterals homework 3: rectangles Gina Wilson answer key

Irina-Kira [14]

Answer:

In the image attached you can find the Unit 7 homework.

We need to findt he missing measures of each figure.

<h3>1.</h3>

Notice that the first figure is a rectangle, which means opposite sides are congruent so,

VY = 19

WX = 19

YX = 31

VW = 31

To find the diagonals we need to use Pythagorean's Theorem, where the diagonals are hypothenuses.

$VX^{2}=19^{2}+31^{2}\\ VX=\sqrt{361+961}=\sqrt{1322} \\VX \approx 36.36$

Also, $YW \approx 36.36$ , beacuse rectangles have congruent diagonals, which intercect equally.

That means, $ZX = \frac{VX}{2} \approx \frac{36.36}{2}\approx 18.18$

<h3>2.</h3>

Figure number two is also a rectangle.

If GH = 14, that means diagonal GE = 28, because diagonals intersect in equal parts.

Now, GF = 11, because rectangles have opposite sides congruent.

DF = 28, because in a reactangle, diagonals are congruent.

HF = 14, because its half of a diagonal.

To find side DG, we need to use Pythagorean's Theorem, where GE is hypothenuse

$GE ^{2}=11^{2}+DG^{2}\\28^{2}-11^{2}=DG^{2}\\DG=\sqrt{784-121}=\sqrt{663}\\ DG \approx 25.75$

<h3>3.</h3>

This figure is also a rectangle, which means all four interior angles are right, that is, equal to 90°, which means angle 11 and the 59° angle are complementary, so

$\angle 11 +59\°=90\°\\\angle 11=90\°-59\°\\\angle 11=31\°$

Now, angles 11 and 4 are alternate interior angles which are congruent, because a rectangle has opposite congruent and parallel sides.

$\angle 4 = 31\°$

Which means $\angle 3 = 59\°$ , beacuse it's the complement for angle 4.

Now, $\angle 6 = 59\°$ , because it's a base angle of a isosceles triangle. Remember that in a rectangle, diagonals are congruent, and they intersect equally, which creates isosceles triangles.

$\angle 9=180-59-59=62$ , by interior angles theorem.

$\angle 8 =62$ , by vertical angles theorem.

$\angle 10 = 180- \angle 9=180-62=118\°$ , by supplementary angles.

$\angle 7 = 118\°$ , by vertical angles theorem.

$\angle 5=90-59=31$ , by complementary angles.

$\angle 2 = \angle 5 = 31\°$ , by alternate interior angles.

$\angle 1 = 59\°$ , by complementary angles.

<h3>4.</h3>

$m\angle BCD=90\°$ , because it's one of the four interior angles of a rectangle, which by deifnition are equal to 90°.

$m\angle ABD = 6\° = m\angle BDC$ , by alternate interior angles and by given. $m\angle CBE=90-6=84$ , by complementary angles.

$m\angle ADE=90-6=84$ , by complementary angles.

$m\angle AEB=180-6-6=168\°$ , by interior angles theorem.

$m\angle DEA=180-168=12$ , by supplementary angles.

<h3>5.</h3>

$m\angle JMK=180-126=54$ , by supplementary angles.

$m\angle JKH=\frac{180-54}{2}=\frac{126}{2}=63$ , by interior angles theorem, and by isosceles triangle theorem.

$m\angle HLK=90\°$ , by definition of rectangle.

$m\angle HJL=\frac{180-126}{2}=27$ , by interior angles theorem, and by isosceles triangle theorem.

$m\angle LHK=90-27=63$ , by complementary angles.

$m\angle = JLK= m\angle HJL=27$ , by alternate interior angles.

<h3>6.</h3>

The figure is a rectangle, which means its opposite sides are equal, so

$WZ=XY\\7x-6=3x+14\\7x-3x=14+6\\4x=20\\x=\frac{20}{4}\\ x=5$

Then, we replace this value in the expression of side WZ

$WZ=7x-6=7(5)-6=35-6=29$

Therefore, side WZ is 29 units long.

<h3>7.</h3>

We know that the diagonals of a rectangle are congruent, so

$SQ=PR\\11x-26=5x+28\\11x-5x=28+26\\6x=54\\x=\frac{54}{6}\\ x=9$

Then,

$PR=5x+28=5(9)+28=45+28=73$

Therefore, side PR is 73 units long.

3 0

3 years ago

Jared made 4 bird houses in 3 days. How many days will it take him to make 28 bird houses.

pogonyaev

4 times 7 = 28

3 times 7 = 21

It will take him 21 days to make 28 bird houses.

6 0

3 years ago