Question

If (x+3) is a factor of f(x) = x³ + Qx² - 4x + 12 then the value of ‘Q’ is *​

Answer 1

Answer:

3

Step-by-step explanation:

divided by (x+3)..

x+3=0..

x=-3..

putting the value of x =-3..f(-3)

x³+qx²-4x-12

(-3)³+q(-3)²-4(-3)-12..

-27+9q+12-12..

-27+9q=0..

9q=27..

q=27/9

q=3..

Answer 2

Answer:

Did you mean  x³ + Qx² - 4x + 12 OR x³ + Qx² - 4x + 12

1. x³ + Qx² - 4x + 12

There are many ways to solve this, but I think this is the easiest method:

(x+3) is a factor of f(x) = x³ + Qx² - 4x + 12

Thus, x+3=0

x= -3 ------- [Substitute in f(x)]

x³ + Qx² - 4x + 12=0

-3³+Q×(-3)²-4×(-3)+12

-27+9Q+12+12=0

9Q=-12-12+27

Q=51/9

Q=17/3

2. x³ + Qx² - 4x + 12

We use the same method...

-3³+Q×(-3)²-4×(-3)-12

-27+9Q+12-12=0

9Q=-12+12+27

Q=27/9

Q=3.

HOPE THIS HELPS :D