Question

if x-2 is a factor of kx^2+kx+20 then k=?

Answer 1

Example
5x + 3
x + 3 / 5 is a factor.
A factor sets the equation to 0.
x + 3 / 5 = 0
x = -3 / 5
Substitute the value of x into the equation.
5(-3 / 5) + 3 = -3 + 3 = 0

Another example
x^2 - 2x + 1
x - 1 is a factor
x - 1 = 0
x = 1
Substitute the value of x into the equation.
(1)^2 - 2(1) + 1 = 1 - 2 + 1 = 0

Answer 2

If it is a factor then the polynomial should be = 0
Thus k2^2+k2+20 = 0
Now find the answer! :)

Answer 3

I just substitued x with 2 okay?

Answer 4

i did substitute x with 2 but kept getting the wrong answer. the answer is -10/3. i am getting 1.25

Answer 5

Can you show your working? I got -10 / 3

Answer 6

ok 1 sec

Answer 7

4k + 2k = -20?
Then calculate!
Good job buddy! :)

Answer 8

thank you so much. I kept writing the equation wrong

Answer 9

k(2)^2 + k(2) + 20 = 0
4k + 2k + 20 = 0
6k + 20 = 0
6k + 20 - 20 = -20
6k = -20
6k / 6 = -20 / 6
k = -10 / 3

Answer 10

i was saying k(4)+k(2) and dividing each over to get 2.5
then i was adding the leftover 1k+1k to make 2k
then dividing by 2.... that's why i got 1.25. thanks!

Answer 11

Synthetic division is a quick way