If it's not what You are looking for type in the equation solver your own equation and let us solve it.
-72=-4a
We move all terms to the left:
-72-(-4a)=0
We get rid of parentheses
4a-72=0
We move all terms containing a to the left, all other terms to the right
4a=72
a=72/4
a=18
| n/3+n/2=-20 | | 63x=54x+18 | | 7+3m=30.4 | | 3a^2-300=0 | | -3w+6w-8=4+5w | | 14.5×42.1+37.9-x=65.3 | | 2x+78=x | | 3+a/3=5 | | 7v-5=3v-1 | | p+8=7 | | 1/2n-12=36 | | 8x-2=-9=6x | | 3+(x-1)/4-(3x+1)/3=x | | 2x-7=(x=7) | | 2x-1=5x+7=90 | | -2.29-5.1z-1.4z=-5.2z+9.02 | | 4x-3.74=8.26 | | 4l-13=7-l | | 4x+9=(X=9) | | ∠7=(4x-2) | | 7+3d=-9-8+6d | | (-u+5)(-4)=16 | | 8x-1=9x+2 | | r-8=-14 | | 4s-7=2s-1 | | 5x-5=9x+3+10 | | -4u+8=28 | | 0,03x=0,05(19000-X)+90 | | 8+x/2=-1# | | 2x+43=10 | | 7h-23=3h+21 | | t=60-2 |