Solve for b
b=\frac{a-4}{2}
Solve for a
a=2\left(b+2\right)
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2b=a-4
Swap sides so that all variable terms are on the left hand side.
\frac{2b}{2}=\frac{a-4}{2}
Divide both sides by 2.
b=\frac{a-4}{2}
Dividing by 2 undoes the multiplication by 2.
b=\frac{a}{2}-2
Divide a-4 by 2.
a=2b+4
Add 4 to both sides.
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Limits
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