If it's not what You are looking for type in the equation solver your own equation and let us solve it.
(x+7)(x-1)=128
We move all terms to the left:
(x+7)(x-1)-(128)=0
We multiply parentheses ..
(+x^2-1x+7x-7)-128=0
We get rid of parentheses
x^2-1x+7x-7-128=0
We add all the numbers together, and all the variables
x^2+6x-135=0
a = 1; b = 6; c = -135;
Δ = b2-4ac
Δ = 62-4·1·(-135)
Δ = 576
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$$\sqrt{\Delta}=\sqrt{576}=24$$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-24}{2*1}=\frac{-30}{2} =-15 $$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+24}{2*1}=\frac{18}{2} =9 $
| 3(0)-y=8 | | 3x^2+23x-34=0 | | 5y+8y=52 | | -2(3x-6)-12=42 | | 3s+2s+s+18=180 | | -3(6r+3)=99 | | (x^2)-x=2x+3 | | -31+-4x=-5-5(1+5x) | | -24-5m=6(-2m-4)-5m | | 30+22z+z+35=180 | | -3x+42=x+14 | | 14x+34=0 | | 4x+3+3x+5=180 | | 6x+54=2x-46 | | 10x+17=5x+117 | | 0.1+2(0.4x+1=x-1x | | 80+65+y+14=180 | | x^2+2+8=50 | | 4+1/3x=4/6+4/2x | | X^2+x-29=1 | | 6+6x-1=9x-1 | | 5+a/2=9 | | (x^2)*(8+3)-12=0 | | z/2-3=8 | | 4x+2/9=10 | | 25(x-8)=250 | | 3x^2-56x+98=0 | | 8x+2(5-x)=3(2x+3)+1 | | 54+c-19+c-3=180 | | x^2*(8+3)-12=0 | | 3(-3r+8)=34-7r | | -96=10x+4 |