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The total surface area of a cuboid is 112cm^2. find the value of x. values given: 10cm and 2cm.

Tatiana [17]

Answer:

x= 5.6

Step-by-step explanation:

we will need to put the information we currently have into an equation:

10•2•x= 112

then multiply 10•2 which equals 20...then the equation wil turn out like this:

20•x=112

now you will isolate the x... but how?? dividing 20 by itslef.. cancelling it out, and if you do one thing to the other side of the equation, you have to do it to the other...

20/20•x=112/20

you will end up with x= 122/20

you can use a calculator for this step, but to practice long division... (check the screen shot thingie)

hope this helped !! ^^

6 0

3 years ago

For which system of equations is (5, 3) the solution? A. 3x – 2y = 9 3x + 2y = 14 B. x – y = –2 4x – 3y = 11 C. –2x – y = –13 x

Alla [95]

The correct answer is:

D) $\left \{ {{2x-y=7} \atop {2x+7y=31}} \right.$ .

Explanation:

We solve each system to find the correct answer.

For A:
$\left \{ {{3x-2y=9} \atop {3x+2y=14}} \right.$

Since we have the coefficients of both variables the same, we will use elimination to solve this.

Since the coefficients of y are -2 and 2, we can add the equations to solve, since -2+2=0 and cancels the y variable:
$\left \{ {{3x-2y=9} \atop {+(3x+2y=14)}} \right. 
\\
\\6x=23$

Next we divide both sides by 6:
6x/6 = 23/6
x = 23/6

This is not the x-coordinate of the answer we are looking for, so A is not correct.

For B:
$\left \{ {{x-y=-2} \atop {4x-3y=11}} \right.$

For this equation, it will be easier to isolate a variable and use substitution, since the coefficient of both x and y in the first equation is 1:
x-y=-2

Add y to both sides:
x-y+y=-2+y
x=-2+y

We now substitute this in place of x in the second equation:
4x-3y=11
4(-2+y)-3y=11

Using the distributive property, we have:
4(-2)+4(y)-3y=11
-8+4y-3y=11

Combining like terms, we have:
-8+y=11

Add 8 to each side:
-8+y+8=11+8
y=19

This is not the y-coordinate of the answer we're looking for, so B is not correct.

For C:
Since the coefficient of x in the second equation is 1, we will use substitution again.

x+2y=-11

To isolate x, subtract 2y from each side:
x+2y-2y=-11-2y
x=-11-2y

Now substitute this in place of x in the first equation:
-2x-y=-13
-2(-11-2y)-y=-13

Using the distributive property, we have:
-2(-11)-2(-2y)-y=-13
22+4y-y=-13

Combining like terms:
22+3y=-13

Subtract 22 from each side:
22+3y-22=-13-22
3y=-35

Divide both sides by 3:
3y/3 = -35/3
y = -35/3

This is not the y-coordinate of the answer we're looking for, so C is not correct.

For D:
Since the coefficients of x are the same in each equation, we will use elimination. We have 2x in each equation; to eliminate this, we will subtract, since 2x-2x=0:

$\left \{ {{2x-y=7} \atop {-(2x+7y=31)}} \right. 
\\
\\-8y=-24$

Divide both sides by -8:
-8y/-8 = -24/-8
y=3

The y-coordinate is correct; next we check the x-coordinate Substitute the value for y into the first equation:
2x-y=7
2x-3=7

Add 3 to each side:
2x-3+3=7+3
2x=10

Divide each side by 2:
2x/2=10/2
x=5

This gives us the x- and y-coordinate we need, so D is the correct answer.

7 0

3 years ago

Given the function g(x) = 4(3)x, Section A is from x = 1 to x = 2 and Section B is from x = 3 to x = 4.

Rudik [331]

The question is defective, or at least is trying to lead you down the primrose path.
The function is linear, so the rate of change is the same no matter what interval (section) of it you're looking at.
The "rate of change" is just the slope of the function in the section. That's
(change in f(x) ) / (change in 'x') between the ends of the section.
In Section A:Length of the section = (1 - 0) = 1f(1) = 5f(0) = 0change in the value of the function = (5 - 0) = 5Rate of change = (change in the value of the function) / (size of the section) = 5/1 = 5
In Section B:Length of the section = (3 - 2) = 1 f(3) = 15f(2) = 10change in the value of the function = (15 - 10) = 5Rate of change = (change in the value of the function) / (size of the section) = 5/1 = 5
Part A:The average rate of change of each section is 5.
Part B:The average rate of change of Section B is equal to the average rate of change of Section A.
Explanation:The average rates of change in every section are equalbecause the function is linear, its graph is a straight line,and the rate of change is just the slope of the graph.

4 0

3 years ago

Susan earned $191.25 last week. She is paid $8.50/h. How many hours did she work?

Oksanka [162]

Answer:

22.5 hours

Step-by-step explanation:

191.25 divided by 8.50 hours will get you the total amount of hours she worked

5 0

2 years ago

Read 2 more answers

Simplify the expresssion 2x^2+8+3x^2+4x-10

nignag [31]

Answer:

x= 0.348 OR X= -1.148

Step-by-step explanation:

Given that:

2x^2+8+3x^2+4x-10

The first step is to rearrange the parameters given, by doing so, we have:

= 2x^2 +3x^2 +4x -10+8

= 5x^2 +4x - 2

The above equation forms the basis of a quadratic equation;

So using quadratic formula

= (-b +/- (√b^2-4ac))/2a

= (-4 +/- (√4^2 -4*5*(-2))/2*5

= -4 +/- (√ 16 - (-40))/10

=( -4 +/- √ 56 ) / 10

=( -4 +√ 56 ) / 10 OR =( -4 - √ 56 ) / 10

= (-4 + 7.48)/10 OR (-4 -7.48)/10

= 3.48/10 OR -11.48/10

= 0.348 OR. -1.148

SO, x= 0.348 OR X= -1.148

4 0

2 years ago

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