If it's not what You are looking for type in the equation solver your own equation and let us solve it.
3x^2+11x+21=0
a = 3; b = 11; c = +21;
Δ = b2-4ac
Δ = 112-4·3·21
Δ = -131
Delta is less than zero, so there is no solution for the equation
| 81x^2-100x=0 | | (X-2)/3=1/x | | F(x)=2^x+2^-x | | 28=x/5-6 | | -2p^2+12p+54=0 | | 8xx=3 | | 1+2x=-2x+5 | | A^2+b^2=10^2 | | -7x+6=18+3x | | 6(x+1)=16 | | x+.18=56 | | 0=-5x+2x+6 | | 24=y-8 | | 12t^2+45-64t=0 | | (2*4)-b=3.6 | | -5x-10+4x=-19 | | -3(6-n)=2n-22 | | X+8=10+4x= | | (10-7)+n=7.1 | | 12x+54=-8x-4(5x+2) | | 12=4x-5x+1 | | 7/(x+3)=x-3 | | 5.5x+4(50-x)=245 | | 2g−2=2 | | 2(w-401)=198 | | 1/4(32x+16)-14=-2/5(45x-45) | | 2(2x+3)-7x+9=18 | | 2(w−401)=198 | | (2x)^2=10^2 | | 24(r+2)=768 | | 5a+a–2a=18 | | 6=5t-1/2t^2 |