If it's not what You are looking for type in the equation solver your own equation and let us solve it.
5x=15x^210-420
We move all terms to the left:
5x-(15x^210-420)=0
We do not support expression: x^210
| 45-9x=25 | | 10000+100t=800+10t^2 | | -(3x+4)-2(x-3)=-5-6x | | 10+5x=5+10x | | 7n+2n-9n+3n-n=16 | | 2+2-1=4x | | x^2-x+79=0 | | 6s–53=10s–97 | | 3m+m-2m=8 | | 10s–97=6s–53 | | 3t+60=5t-100 | | -8s−10=-9s | | 11v-11v+5v+4v=9 | | 9m=-9+8m | | 1/2b+3=8 | | x=5+2/5 | | 7y-1=2y+10 | | 2(x−3)=2(x−5) | | (-3x^2+7x-42)=0 | | 28=8x+1-3x | | -90=-5(k+5) | | 3z+4z-6z=7 | | (4x-7)(x-8)=0 | | −4x+30=18 | | 32x=704x=704/32 | | x-103=8(2x+3)-7 | | 4x;x=7/2 | | 74=6n-4 | | 16a+2a-8a-9a=13 | | 35x^2−22x+7=4 | | -12-(2v+5v)=0 | | 16a+2a−8a−9a=13 |