what is the evaluation?

Let u = 2x+1. Then 2x-5 = 2x+1-6 = u-6, and 2x-2 = 2x+1-3 = u-3.

So,

2x-5=3(2x-2)-15 becomes,

u-6 = 3(u-3)-15=> u-6 = 3u-24

=> 18 = 2u

=> u = 9

Answer: 2x+1 = 9

what is the evaluation?

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Scottsdale, AZ

Let u = 2x+1. Then 2x-5 = 2x+1-6 = u-6, and 2x-2 = 2x+1-3 = u-3.

So,

2x-5=3(2x-2)-15 becomes,

u-6 = 3(u-3)-15=> u-6 = 3u-24

=> 18 = 2u

=> u = 9

Answer: 2x+1 = 9

Saugus, MA

2x-5=3(2x-2)-15

2x-5=6x-6-15

2x-5=6x-21

21-5=6x-2x

16=4x

x=4

2x+1=2(4)+1=8+1=9

Chicago, IL

One thing which might be confusing in this problem is the wording. "What is the evaluation of 2x+1" is just funky math-speak for "what number is 2x+1 once you plug in x." To do this, we can solve the equation they give us, and then we'll plug in x.

Let me show you a similar example: Given that 3x - 2 = 4(2x - 2) - 14, what is the evaluation of 3x + 2?

We'll start by solving for x:

3x - 2 = 4(2x - 2) - 14

3x - 2 = 8x - 8 - 14

3x - 2 = 8x - 22

+22 +22

3x + 20 = 8x

-3x -3x

20 = 5x

/5 /5

4 = x

Now we know that x is 4. Therefore, 3x+2 *evaluates *to 3(4) + 2, which is better known to its friends as 14.

Take home message: The phrase "evaluation" means "what number do you get when you plug in for all of the variables." Hopefully this is enough to help you make some progress. :-)

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