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goldfiish [28.3K]

2 years ago

8

12 of the students in a Geometry class passed a Geometry test. If these students are 80% of all the students in the class, how m

any students are in this Geometry class?

1 answer:

VikaD [51]2 years ago

6 0

Answer:

15

Step-by-step explanation:

12/8 =1.5 * 10 =15

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Thalia, a quiz show contestant, answered 20 questions. She was awarded 2 points for every correct answer that she gave, but she

DIA [1.3K]

The viewer mistakenly determined that one of the equations in the system should be 2 x + y = 28. Instead modifications should have been made before applying the equation.

<h3>What is an Equation ?</h3>

An equation is a mathematical statement formed when two algebraic expressions are equated using an equal sign.

Total Questions = 20

Total Points = 28

Correct Answers = +2 points

Incorrect Answers = -1 point

The viewer represents the correct answers with x and the incorrect ones with y.

x+y = 20

for every correct answers 2 points;

and for every incorrect answers, -1 point

This can be written as

2x-y = 28

The viewer's mistake is that; instead of subtracting total incorrect points from the correct points, the viewer added them together;

now

2x-y = 28

x+y = 20

On adding the equations

]3x = 48

x = 16

y = 4

This means that the contestant answered 16 questions correctly and 4 questions incorrectly

The viewer mistakenly determined that one of the equations in the system should be 2 x + y = 28.

To know more about Equation

brainly.com/question/10413253

#SPJ1

3 0

1 year ago

Solve the inequality<br> 7+7(x+4)>21

Kryger [21]

Answer:

x>-2

Step-by-step explanation:

Hi there!

We are given the inequality 7+7(x+4)>21, and we want to solve it

Solving an inequality is a lot like solving an equation; we want to isolate x on one side by itself.

So to start, we'll preform the distributive property on 7(x+4) (multiply x by 7, then multiply 4 by 7 and add those two together).

7+7x+28>21

Now combine like terms.

7x+35>21

Subtract 35 from both sides

7x>-14

Divide both sides by 7

x>-2

Hope this helps!

8 0

2 years ago

Three years ago, Jolene bought $625 worth of stock in a software company. Since then the value of her

Lesechka [4]

Answer:

The stock is worth 765.65 today.

Step-by-step explanation:

$$625*1.07^{3}$ =765.65

8 0

2 years ago

Help!! 50 points and brainliest!

Viktor [21]

Answer:

Second choice:

$x=2t$

$y=4t^2+4t-3$

Fifth choice:

$x=t+1$

$y=t^2+4t$

Step-by-step explanation:

Let's look at choice 1.

$x=t+1$

$y=t^2+2t$

I'm going to subtract 1 on both sides for the first equation giving me $x-1=t$ . I will replace the $t$ in the second equation with this substitution from equation 1.

$y=(x-1)^2+2(x-1)$

Expand using the distributive property and the identity $(u+v)^2=u^2+2uv+v^2$ :

$y=(x^2-2x+1)+(2x-2)$

$y=x^2+(-2x+2x)+(1-2)$

$y=x^2+0+-1$

$y=x^2$

So this not the desired result.

Let's look at choice 2.

$x=2t$

$y=4t^2+4t-3$

Solve the first equation for $t$ by dividing both sides by 2:

$t=\frac{x}{2}$ .

Let's plug this into equation 2:

$y=4(\frac{x}{2})^2+4(\frac{x}{2})-3$

$y=4(\frac{x^2}{4})+2x-3$

$y=x^2+2x-3$

This is the desired result.

Choice 3:

$x=t-3$

$y=t^2+2t$

Solve the first equation for $t$ by adding 3 on both sides:

$x+3=t$ .

Plug into second equation:

$y=(x+3)^2+2(x+3)$

Expanding using the distributive property and the earlier identity mentioned to expand the binomial square:

$y=(x^2+6x+9)+(2x+6)$

$y=(x^2)+(6x+2x)+(9+6)$

$y=x^2+8x+15$

Not the desired result.

Choice 4:

$x=t^2$

$y=2t-3$

I'm going to solve the bottom equation for $t$ since I don't want to deal with square roots.

Add 3 on both sides:

$y+3=2t$

Divide both sides by 2:

$\frac{y+3}{2}=t$

Plug into equation 1:

$x=(\frac{y+3}{2})^2$

This is not the desired result because the $y$ variable will be squared now instead of the $x$ variable.

Choice 5:

$x=t+1$

$y=t^2+4t$

Solve the first equation for $t$ by subtracting 1 on both sides:

$x-1=t$ .

Plug into equation 2:

$y=(x-1)^2+4(x-1)$

Distribute and use the binomial square identity used earlier:

$y=(x^2-2x+1)+(4x-4)$

$y=(x^2)+(-2x+4x)+(1-4)$

$y=x^2+2x+-3$

$y=x^2+2x-3$ .

This is the desired result.

3 0

3 years ago

Read 2 more answers

James and Amy play 3 more games.They have played the same number of games as last week .Fill in the blanks to make the equation

Fiesta28 [93]

Question is Incomplete; Complete question is given below;

James and Amy played 12 games of checkers last week. This week they played 7 games on Monday and 2 games on Wednesday.James and Amy play 3 more games. They have played the same number of games as last week. Fill in the blanks to make the equation true. Use +,-, or =. 12_7_2_3 Explain how you chose the symbols.

Answer:

12<u> = </u>7<u> + </u>2<u> + </u>3

Step-by-step explanation:

Given:

Number of games played last week = 12

Number of games played on Monday this week = 7

Number of games played on Wednesday this week = 2

Also given:

James and Amy play 3 more games.

So Number of games played more = 3

We need to fill in the blanks 12 __ 7__2__3 with signs '+', '-','='.

Solution:

It is given that they have played the same number of games as last week.

So we can say that;

Number of games played last week is equal to Number of games played on Monday this week plus Number of games played on Wednesday this week plus Number of games played more.

framing in equation form we get;

$12 = 7 + 2+3$

Hence we have fill the blanks as 12<u> = </u>7<u> + </u>2<u> + </u>3.

8 0

3 years ago