Question

If s(x) = 2-x² and f(x) = 3x, which value is equivalent to (sf)(-7)?
150

Answer 1

443

(I explained why -439 is wrong and why 443 is correct)

Explanation:

Function of F to x is 3x S to x is 2-x²

Function of S will be equal to Function of F to -7

f(-7) = 3 x -7 = -21

Now function of S will be to -21

S(-21) = 2-x²

= 2-(-21²) = 2 - (-441)

= 2 + 441

= 443

if it was 2 - (x)² it would have been 2 - 441 and it would have been -439. but don't forget, a negative number powered to even number would make positive only when the number is inside paranthesis, if the it's not inside the paranthesis it will make negative, and subtracting negative is - - which will make +.

The answer -439 Is wrong, 443 Is correct.