Question

If x+2 is a factor of the polynomial: 3x²+kx, then the value is​

Answer 1

k = 6

Explanation:

(x+2) is a factor of 3x²+kx so if we solve (x+2) = 0 that will give us one of the solutions of x for 3x²+kx = 0, and then we can substitute that solution in and find the value of k.

So to find a solution, (x+2) = 0 and therefore x = -2

Now substitute x = -2 into 3x²+kx = 0

so 3(-2)²+k(-2) = 0

12 - 2k = 0

2k = 12

k = 6