12-r=21

Simple and best practice solution for 12-r=21 equation. Check how easy it is, and learn it for the future. Our solution is simple, and easy to understand, so don`t hesitate to use it as a solution of your homework.

If it's not what You are looking for type in the equation solver your own equation and let us solve it.

Solution for 12-r=21 equation: 


Simplifying
12 + -1r = 21

Solving
12 + -1r = 21

Solving for variable 'r'.

Move all terms containing r to the left, all other terms to the right.

Add '-12' to each side of the equation.
12 + -12 + -1r = 21 + -12

Combine like terms: 12 + -12 = 0
0 + -1r = 21 + -12
-1r = 21 + -12

Combine like terms: 21 + -12 = 9
-1r = 9

Divide each side by '-1'.
r = -9

Simplifying
r = -9

See similar equations:

| X^4-6x^2+25=0 | | -3(5x+3)=-15x-5 | | 8-q=-31 | | -23=-6x+-8+-9x | | -63=-3+6(2+3n) | | 14=2m+1+3 | | 14-v=10 | | x^2+8t+9=0 | | 5(2q-3)=5 | | 10times1/3 | | 5-u=19 | | 3t+4x=6-2x | | 5n+5(3+2n)=75 | | 9-s=7 | | 3.5+0.25p=20 | | 5x-1-2=3x-7 | | -8v+3v=12.5 | | 8-t=-12 | | 89=111-m | | 4=-4(7-u) | | 66=-4x-2 | | x+2y=-28 | | 1/2is5-/12 | | 5i(7i)=0 | | K+k=16.3 | | https://static.k12.com/bank_packages/files/media/mathml_18d7dccaf6fc5a75358663e68a528639d7f671fe_1.gif | | 41=-4x+5 | | -2e+4=-8 | | -12=4(6+t) | | C+c=104 | | 3x^2-28x+60= | | 2a-7=38 |

Equations solver categories