Question

Solve x2 − 7x + 12 = 0.

x = −3, x = −4
x = 3, x = 4
x = 2, x = 6
x = −2, x = −6

Answer 1

factor the left part of the equation

Answer 2

x^2 - 7x + 12 = 0
x^2 -4x - 3x + 12 = 0

now factor the above by grouping

Answer 3

- that means factor x^2 - 4x and - 3x + 12

then simplify

Answer 4

I agree

Answer 5

@DarkMoonZ what did you get after following @welshfella directions

Answer 6

Ok wait

Answer 7

x (x - 4) and 3(4-x)

Answer 8

Sorry I had been AFK lol and thanks @welshfella

Answer 9

first one is write

notice it -3 x + 12 negative 3

Answer 10

oh ok

Answer 11

so its -3(4-x)

Answer 12

no its -3( x - 4) If you expand that you'll see it comes bakc to -3x + 12
so we got

x(x - 4) - 3(x - 4) = 0

Answer 13

Ok

Answer 14

now e can simplify this further because there is (x - 4) in both parts

Answer 15

so take x - 4 out and what have we got left?

Answer 16

-3x=0

Answer 17

or just X = -3

Answer 18

no what i mean by taking x - 4 out is using it as a factor and what left becomes the other factor


similar to 3 x + 3y

- 3 is common to both 3x and 3y so we take 3 'out' and it becomes a factor

3x + 3y = 3 (x + y) The x+ y becomes the other factor.

Answer 19

oh ok....

Answer 20

x(x - 4) - 3(x - 4) = 0

(x - 4) is common so we take it out and whats left ( the x - 3 0 goes in the other parentheses
so we have

(x - 4)(x - 3) = 0

Answer 21

now either x - 3 = 0 or x - 4 = 0
making x = 3 , 4

Answer 22

Ok

Answer 23

thanks