functions/real numbers/expressions

Question

Suppose that the functions r and s are defined for all real numbers x as follows.

 

r(x)=4x^2

s(x)=2x

 

Write the expressions for (R-S)(X) and (R+S)(X) and evaluate (R x S)(-2)

 

 

(R-S)(X)= ?

(R+S)(X)= ?

(R x(multiply) S)(-2) = ? 

Answer 1

(r - s)(x) = r(x) - s(x)

(r - s)(x) = 4x² - 2x

 

(r + s)(x) = r(x) + s(x)

(r + s)(x) = 4x² + 2x

 

(r · s)(x) = ((r)x))((s(x))

(r · s)(x) = 4x²(2x)

(r · s)(x) = 8x³

 

(r · s)(-2) = 8(-2)³