Question

If f(x)=-x2(power of ) -5x+18, what is f(-5) a.18 b.68 c. -18 d. -68 e. none of these

Answer 1

Answer:

As

• $f(-5)=18$

Hence, the option 'a' is true.

Step-by-step explanation:

Given the expression

$f\left(x\right)=-x^2-5x+18$

Putting x = -5 in the expression

$f\left(-5\right)=-\left(-5\right)^2-5\left(-5\right)+18$

          $=-\left(-5\right)^2+5\cdot \:5+18$

          $=-5^2+5\cdot \:5+18$

          $=-5^2+25+18$

          $=43-5^2$

          $=43-25$

          $=18$

Therefore,

• $f(-5)=18$

Hence, the option 'a' is true.