Evaluate the function. f(x) = - x^(2) - 7x - 5 Find f( - 5)

Question

asked Jul 6, 2021 74.1k views

1 Answer

Czheo · Answer 1 · 2021-07-12T17:51:37+0000

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Step-by-step explanation:

Everywhere you see an x, replace it with -5. Then use the order of operations PEMDAS to simplify

$f(x) = -x^2 - 7x - 5\\\\f(-5) = -(-5)^2 - 7(-5) - 5\\\\f(-5) = -(25) - 7(-5) - 5\\\\f(-5) = -25 + 35 - 5\\\\f(-5) = 10 - 5\\\\f(-5) = 5\\\\$

Keep in mind that for the x^2 term, you are squaring all of x = -5, which includes the negative as well. So that means

x^2 = (-5)^2 = (-5)*(-5) = 25

but sticking a negative out front makes

-x^2 = -(-5)^2 = -25