If it's not what You are looking for type in the equation solver your own equation and let us solve it.
5c-2c=21
We move all terms to the left:
5c-2c-(21)=0
We add all the numbers together, and all the variables
3c-21=0
We move all terms containing c to the left, all other terms to the right
3c=21
c=21/3
c=7
| 38=8m+4 | | 8m+4=38 | | -124=14k | | 15n+9=-201 | | 4(x-6)=x+5+3x | | (i=3)(i=4)4i= | | w/6+73=84 | | x-7=x-10 | | i=3i=44i= | | 5x=4.79 | | 5x3=(5x+1) | | 10y-4=4y+13+6y-17=y | | –7.18=2(z−9.45) | | 60×-25y=15 | | 0.50y=4+0.50y | | 4x-7=8x+@ | | 3(-5a-4)=3(1-a)-3 | | 7.29=2.43(r+1) | | X=240y | | -5p+6-p=-12 | | (2^n)=16 | | 12w+11=155 | | 10y-4=4y+13+6y-17 | | 5d-8=87 | | 5x-2x^2=63 | | 47=(k+1) | | 0.15x=24+0.11x | | 15x-13x=18 | | 4x+12=2x-2-6 | | 35=(4m+3) | | 99x/101=3/2 | | 1210=c5 |