If it's not what You are looking for type in the equation solver your own equation and let us solve it.
x^2-40x-15=0
a = 1; b = -40; c = -15;
Δ = b2-4ac
Δ = -402-4·1·(-15)
Δ = 1660
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}$$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$
The end solution:
$\sqrt{\Delta}=\sqrt{1660}=\sqrt{4*415}=\sqrt{4}*\sqrt{415}=2\sqrt{415}$$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-40)-2\sqrt{415}}{2*1}=\frac{40-2\sqrt{415}}{2} $$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-40)+2\sqrt{415}}{2*1}=\frac{40+2\sqrt{415}}{2} $
| x/5+x/4=15 | | 5x+45=12x+56=1 | | (e+4)X5=25 | | n+n-1+n+5=64 | | 3.2x-7=-7.8x+3.6 | | 109=9u | | x2+x–30=0 | | 3z/7+5=-8 | | x^2+x–30=0 | | 13y=40+8y | | 5x=8-27 | | 2.2=6.7-0.9x | | –126=3x | | 14+5=-5-6(-3x-15)+5 | | 18m+18=3m+3 | | |4x-1|=7x | | =+17x1220x. | | 8x+4(4-7x)=4(-7x+2) | | 3/4=x/6.1 | | 6x^2−12=−1 | | -2v+14=-5(v-1) | | 3+8x=4x | | 5=170t-16t^2 | | 1/6=x/15 | | 2.1x=7.14 | | x+2x+x-30=180 | | 15/x=45/24 | | 8(y+4)=-3y+43 | | 7x=1=15x | | 9-x=x+9 | | 1/x=4/10 | | 2/x=4/20 |