Question

I don’t understand this one

Answer 1

see below

Explanation:

Put -1 where x is in each expression and evaluate it.

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You will find that the expression is zero when the numerator is zero. And you will find the numerator is zero when it has a factor that is equivalent to ...

(x +1)

Substituting x=-1 into this factor makes it be ...

(-1 +1) = 0

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Evaluating the first expression, we have ...

`(4(x+1))/((4x+5))=(4(-1+1))/(4(-1)+5)=(4\cdot 0)/(1)=0`

This first expression is one you want to "check."

You can see that the reason the expression is zero is that x+1 has a sum of zero. You can look for that same sum in the other expressions. (The tricky one is the one with the factor (x -(-1)). You know, of course, that -(-1) = +1.)