Question

Multiply. (x – 4)(x2 – 3x + 5)

Answer 1

ok !
\[\large{(x-4)(x^2-3x-5)=x(x^2-3x-5)-4(x^2-3x-5)}\]
can u solve this ?

Answer 2

can you help me step by step ?

Answer 3

ok ! see we have an identity : \(\huge{x(y-z)=xy-xz}\) or for trinomials we have :
\[\huge{x(a-b-c)=xa-xb-xc}\]
BINOMIALS * TRINOMIALS
\[{(x-y)(a-b-c)=x(a-b-c)-y(a-b-c)=xa-xb-cx-ay+yb+yc}\]

apply this identity here :

given \(\huge{(x-4)(x^2-3x-5)}\)
\[\huge{x(x^2-3x-5)-4(x^2-3x-5)}\]
\[\large{x(x^2)-x(3x)-x(5)-4(x^2)-4(-3x)-4(-5)}\]
\[\huge{x^3-3x^2-5x-4x^2+12x+20}\]
\[\huge{x^3-3x^2-4x^2-5x+12x+20}\]
U can simplify this further

Answer 4

is it x3 + 5x2 + 5x – 20

Answer 5

no @GhettoBaby
\[\huge{x^3-3x^2-4x^2+12x-5x+20}\]
\[\huge{x^3-7x^2+7x-20}\]

Answer 6

you mean 17x-20

Answer 7

@mathslover x3 – 7x2 + 17x – 20