If it's not what You are looking for type in the equation solver your own equation and let us solve it.
x-15+2x=21
We move all terms to the left:
x-15+2x-(21)=0
We add all the numbers together, and all the variables
3x-36=0
We move all terms containing x to the left, all other terms to the right
3x=36
x=36/3
x=12
| 4+5x/6=9 | | 18^2-11x-1=0 | | 2(x+6)=3(3x-4) | | -.2e+5+.6e=30+7 | | 4×c-2=18 | | 4c-3c=-14 | | √121r=11r | | (1/4x+1/2)x12=(1/6x+2) | | –10+9v=10−v | | 2x+2(x-4.5)=44 | | 5y=20/4 | | 4m+7=40 | | J(-2)=(-3x+1) | | 4+9z+z2=0 | | 2x-12=8x+6 | | x−137.4=118.8 | | F(x)=0.55 | | 4–d=9 | | x^2+11x+16=9 | | 9=6-3f | | 6=2(p+4) | | -4(r+-5)=16 | | -3(v+9)=-18 | | 7v+5/2+4v-5/6=10 | | 3(r-14)=12 | | 5(6y-3)-3(6-5y)=48 | | 8(4-2x)=16 | | -5x+4x^2=0 | | 4(x+1)=9.5 | | 3-4(w)=55 | | 4 | | 4x+6=3x+10=2x+28 |