Question

If f(x) = x 2+ 8x – 5 and g(x) = 9x – 12, write the polynomial, in standard form, for the following.
a) (f +g)(x)
b) (f ∙ g)(x)

Answer 1

Step-by-step explanation:

$1.$

$\implies \: (f + g)x = f(x) + g(x)$

$\implies \: {x}^{2} + 8x - 5 + 9x - 12$

$\implies \: {x}^{2} + 17x - 17 = 0$

$2.$

$(f \times g)x = f(x) \times g(x)$

$\implies \: ( {x}^{2} + 8x - 5)(9x - 12)$

$\implies \: 9 {x}^{3} - 12 {x}^{2} + 72 {x}^{2} - 96 - 45x + 60$

$9 {x}^{3} + 60 {x}^{2} - 45x + 36$