solve x²+7x+12= 0
I need to know how to work it out - please help!!!!!
x² + 7x + 12 = 0
We need to find factors of 12 that add up to 7.
They must be 3 and 4
(x + 3)(x + 4) = 0
One, or both, of those factors on the left must equal zero.
(Multiplying by zero produces a zero result.)
Set each one to zero and solve for x.
(x + 3) = 0
x = -3
(x + 4) = 0
x = -4
Check both answers using the original equation.
x² + 7x + 12 = 0
-3² + 7(-3) + 12 = 0
9 - 21 + 12 = 0
0 = 0
x² + 7x + 12 = 0
-4² + 7(-4) + 12 = 0
16 - 28 + 12 = 0
0 = 0
So, x = -3 and x = -4 are solutions.
If you graph this equation, you will get a parabola that crosses
the x axis at two points: (-3, 0) and (-4, 0)