Question

x cube + kx +12 = ( x-6) (x-2) find value of x

Answer 1

you did mistake in typing ,
question may be,
x² + kx + 12 = (x - 6)(x - 2) then , find value of k ?


x² + kx + 12 = (x - 6)(x - 2)
= x(x - 2) -6(x - 2)
= x² - 2x - 6x + 12
= x² - 8x + 12

now, compare LHS to RHS,
you got k = -8