Question

Let f(x)=x²+3x-4 and g(x)=x+5 Find f(x) • g(x)

A) x³+3x²+16x-20
B) x³+5x²+14x-20
c) x³+8x²+11x-20
D) x³+9x²+19x-20​

Answer 1

c) x^3 + 8x^2 + 11x - 20.

Explanation:

f(x) . g(x) = (x + 5)(x^2 + 3x - 4)

= x(x^2 + 3x - 4) + 5(x^2 + 3x - 4)

= x^3 + 3x^2 - 4x + 5x^2 + 15x - 20 Simplifying like terms:

= x^3 + 8x^2 + 11x - 20.

Answer 2

The correct option is C.

Explanation:

Given:

f(x)=x²+3x-4 and g(x)=x+5

We have to find f(x) • g(x)

In this question simply multiply the functions:

(x²+3x-4) (x+5)

Multiply each element of 2nd bracket with the every element of first bracket.

= x(x²+3x-4)+5(x²+3x-4)

= x^3+3x^2-4x+5x^2+15x-20

Now solve the like terms:

= x^3+8x^2+11x-20

Thus the correct option is C....