Question

If (x+3) divides x^2+kx+12 then k​

Answer 1

Answer:

Step-by-step explanation:

That means:

x = -3

We know by factor theorem that if the remainder is zero, the expression divides the other expression perfectly.

So,

f(x) = x^2 + kx + 12

f(-3) = 9 - 3k + 12

We know that f(-3) = 0; since (x+3) perfectly divides f(x).

So,

-3k + 9 + 12 = 0  

-3k = -21

k = -21/-3

k = 7

I hope this helped!!

Regards,

Lilac584