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## Comment on

Evaluate Expression with 37’s## If I let a=37, then a^2-23a-a

## What answer are you getting

What answer are you getting when you evaluate the expression?

## Hi if i let x=37, I get the

then, x^2 - 38x - x

then, x^2 - 39x

then, x(x-39)

which gives me 0 and 39 as possible values for x when I put the equation = 0

I chose 0 because its one of the answer choices. I know its wrong from the video but could you explain why.

## The small error you just made

The small error you just made is very common.

Once you saw got to the EXPRESSION x(x-39), you transformed it into the EQUATION x(x-39) = 0.

However, there is no such EQUATION.

We still need to find the VALUE of x(x-39) when x = 37

So, we must take x(x-39) and replace the x's with 37's

We get: 37(37-39)

Simplify to get: 37(-2)

Evaluate to get: -74

Does that help?

Cheers,

Brent

## It did! ;)

## Could you factor out 37 after

I got the same answer, but is this just a coincidence? Or even if it's not a coincidence. Is there more room to make a mistake by factoring out 37 instead of the way you showed above. I hope that made sense. Thanks

## Great idea!

Great idea!

We can definitely evaluate the expression by first factoring out of the 37.

We get:

37² - (23)(37) - 37 - (37)(15) = (37)(37) - (23)(37) - 37 - (37)(15)

= 37(37 - 23 - 1 - 15)

= 37(37 - 23 - 1 - 15)

= 37(-2)

= -74

Cheers, Brent

## Very Clear

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