Need help writing some expressions and 1 evaluation

Suppose that the functions "s" and "t" are defined for all real numbers "x" as follows

s(x) = x-5
t(x) = 4x+2

Write the expressions for ( s * t )(x) and ( s - t )(x) and evaluate ( s + t )(-2)

s(x) = x-5
t(x) = 4x+2

A) ( s * t )(x) means to multiply the functions:
(x-5)(4x+2)= 4x^2 -18x -10

B) ( s - t )(x) means to subtract the functions:
(x-5)- (4x+2)= -3x -7

C) evaluate ( s + t )(-2)
You can do this two ways: find s(-2) + t(-2)
Or find (s+t)(x); then plug in x= -2

s(-2)= -2-5= -7 and t(-2)= 4(-2)+2= -6
Then -7+ -6= -13
----or---
(s+t)(x)= (x-5)+ (4x+ 2)= 5x -3
(s+t)(-2)= 5(-2)-3= -13

I hope this helps!