If it's not what You are looking for type in the equation solver your own equation and let us solve it.
-0.4x^2+5x+15=0
a = -0.4; b = 5; c = +15;
Δ = b2-4ac
Δ = 52-4·(-0.4)·15
Δ = 49
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{49}=7$$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-7}{2*-0.4}=\frac{-12}{-0.8} =+15 $$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+7}{2*-0.4}=\frac{2}{-0.8} =-2+0.4/0.8 $
| 2x+34=7x-11 | | x²-26x=56 | | x-3/5=17 | | F(x)=12.50x | | x-0.20x-80=24 | | M3-6m2+11m-6=0 | | (3x-1)+(2x-24)=90 | | (3x+1)^2=-75 | | 2/x-3+4/x+3=8/x^2-9 | | 5(20+p)=2(30=p) | | .08-2t=1-3t | | -63=1-8x=49 | | 1/4x^2+2x-12=0 | | 5z+11=z-5 | | -3(-7x-6)-7=x-29 | | 7z-5=8z | | K^2+16k+100=0 | | 81u^2-36=0 | | x/14+7/14=1-3/2x | | 52x=11 | | 10-3(2x+1)=8x-1 | | 0.3x+5.6=31 | | 144h^2+48=73 | | 3-4b=7 | | .13(4x-20)=0.5x-6 | | 12(10x-9)=-12(9+8x) | | 1.81=(37.5-u)/4 | | (5/6x)-3+(1/3x)=(7/24x)+1/8 | | 8a-12a+6a=14 | | 9n+6/8=7n-2(n-2) | | 2.5/1.25=8/y | | 7(v-7)=-8v+26 |