If it's not what You are looking for type in the equation solver your own equation and let us solve it.
6x^2-10x^2-21=0
We add all the numbers together, and all the variables
-4x^2-21=0
a = -4; b = 0; c = -21;
Δ = b2-4ac
Δ = 02-4·(-4)·(-21)
Δ = -336
Delta is less than zero, so there is no solution for the equation
| 5(x-2)+6=2x-4+3x | | 3x+1/4-7-x/2-2=4x-3/3-9-5x/6 | | 9.5+9(1+5.5d)=27.5 | | 5r+30=500 | | 59-19=5(x-5) | | 6x5+(2/3)=14 | | (6x5)+2/3=14 | | -1/2x+1=-x-8 | | (12-2x)^2=0 | | 7w+8-2w=6w-9 | | -13-(-50)=a | | 25x+4=27x-4 | | 3x+9+x+x-14=180 | | 4y=40y-20 | | 5.5(1+7.5f)=28.5 | | -7(3/9)=a | | 2x-5=6x-15 | | 2y^2-11y=22 | | 60+8x+2+70=180 | | 2.6+4=5(x+1)-3(x+2) | | 2y-6=y-5 | | -140=-4+19a-2a | | 0=q/5-4 | | 85.00+7.50m=130 | | -3/9-6/9=a | | 17-2p=2p+5+5p | | 4p+5p+10=270 | | -5x-15=-3x+11 | | 3^8x-7=81 | | 3x-15=4x-5 | | 29x-1+28x+3=180 | | 325=80+75x1 |