Question

If s(x)=2-x^2 and t(x)=3x, which value is equivalent to (s*t)(-7)?

Answer 1

(s*t)(-7) = 987

Explanation:

s(x) = 2 - x²

t(x) = 3x

To find (s*t)(x), multiply s(x) and t(x).

(s*t)(x) = (2 - x²)(3x)

(s*t)(x) = 6x - 3x³

Now that you have (s*t)(x), plug -7 in.

(s*t)(-7) = 6(-7) - 3(-7)³

(s*t)(-7) = 6(-7) - 3(-343)

(s*t)(-7) = -42 + 1029

(s*t)(-7) = 987