If it's not what You are looking for type in the equation solver your own equation and let us solve it.
t in (-oo:+oo)
t/21 = 21 // - 21
t/21-21 = 0
1/21*t-21 = 0 // + 21
1/21*t = 21 // : 1/21
t = 21/1/21
t = 441
t = 441
| -15x+6=-27 | | 14.3=4.1r-6.8r+4r | | 10x+12=2(4x+8) | | -20f=780 | | 10+7x=33 | | 20+7x=32 | | m(5m-3)=0 | | -7g=189 | | 3x^7/2x^4 | | -9x-8=-10x+4 | | (4-x)+1whenx=-2 | | -5x^2+x-5=0 | | y-4(-1/2)=-10 | | 7-0.2=3 | | 2(x+3+2)=x | | 1/2(6y_2)=2 | | -49-5x=76-10x | | y+216=-332 | | (m+8)(m-8)-(m-9)(m-9)= | | -2x-82=107-11x | | X^2+6x+120=0 | | 7a+10=6a+18 | | 5(-2)-y=8 | | -15+12x=30+9x | | 0.8(2-g)=24 | | x+2-4x=-4 | | -62+7x=18+3x | | y=3/2(9)-13/2 | | 3mn-6n=0 | | -62+8x=106+x | | 7f=28.70 | | -y^2+28y-27= |