Question

if x-2 is factor of x^3 + 3ax-2a then a = ​

Answer 1

Answer:

a = -2

Step-by-step explanation:

Given, g(x) = x - 2 is the factor of----

p(x) = x³ + 3ax -2a

so, by factor theorem p(2) must be equal to zero.

or, p(2) = 0

or, 2³ + 3a × 2 -2a = 0

or, 8 + 6a - 2a = 0

or, 8 + 4a = 0

or, 4a = -8

or, a = -8 /4

or, a = -2

Answer 2

Step-by-step explanation:

$x - 2 = 0 \\ x = 2 \\ {x}^{3 } + 3ax - 2a \\ {2}^{3} + 3 \times a \times 2 - 2a = 0 \\ 8 + 6a - 2a = 0 \\ 8 + 4a = 0 \\ 4a = - 8 \\ a = - 8 \div 4 = - 2$