Suppose that the functions s and t are defined for all real numbers x as follows s(x) x-4 and t(x)=4x+1 write the expressions for (s•t) and (x) and (s+t) and evaluate (s-t)(-2)

Answer 1

(s•t)(x) = s(t) = t-4 = (4x+1)-4 = 4x-3
so, (s•t)(-2) = 4(-2) - 3 = -11
Or, s(t(-2)) = s(-7) = -7-4 = -11

(s+t)(x) = s(x)+t(x) = x-4 + 4x+1 = 5x-3
do s-t similarly, and plug in -2 for x