If it's not what You are looking for type in the equation solver your own equation and let us solve it.
x in (-oo:+oo)
-7 = x/(-3) // - x/(-3)
-(x/(-3))-7 = 0
1/3*x-7 = 0 // + 7
1/3*x = 7 // : 1/3
x = 7/1/3
x = 21
x = 21
| 12z-15=9z+3 | | 27=9-3h | | (42*5)-(55*14)= | | 10y=-50 | | (2z-8)(z+5)=0 | | 2x+5x-3=0 | | 15x+x+3x+15=180 | | (d+8)(d-1/2)=0 | | (c+(3/4))(c-6)=0 | | x^4+14x^2+56=0 | | 3x-2(x-5)=2(x+3)-8 | | (d+8)(d-(1/2))=0 | | 9x-4+8x+2+13x+30+19x-11=360 | | (n-8)(n-9)=0 | | 20-6x+4=-2+3x | | (p+15)(p+24)=0 | | 3x+5y=15fory | | 4/5x-12=-4 | | 9(R-5)=R+13-2R | | x^4+14x^2+54=0 | | 36x^2-1/5x^2-45=0 | | 88=5x+1/4x | | x^4-3x^2=-2x^2 | | 14p-5q-7p-3q= | | 96=6z+6 | | 323x^2-8x-16=0 | | 4k+2/k=k | | 98-4x=41x+23 | | 10c^2+11c+3=0 | | 5x^2y^4+x= | | 8+8x-x^2=0 | | 3x+55=9x |