Solve for x, y
x=-\frac{3b}{2}+63
y=\frac{3b}{2}-9
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\frac{1}{3}x+\frac{b}{2}=21,x+y=54
To solve a pair of equations using substitution, first solve one of the equations for one of the variables. Then substitute the result for that variable in the other equation.
\frac{1}{3}x+\frac{b}{2}=21
Pick one of the two equations which is more simple to solve for x by isolating x on the left hand side of the equal sign.
\frac{1}{3}x=-\frac{b}{2}+21
Subtract \frac{b}{2} from both sides of the equation.
x=-\frac{3b}{2}+63
Multiply both sides by 3.
-\frac{3b}{2}+63+y=54
Substitute 63-\frac{3b}{2} for x in the other equation, x+y=54.
y=\frac{3b}{2}-9
Subtract 63-\frac{3b}{2} from both sides of the equation.
x=-\frac{3b}{2}+63,y=\frac{3b}{2}-9
The system is now solved.
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