Solve for a
a=\frac{4\left(b+20\right)}{5}
Solve for b
b=\frac{5\left(a-16\right)}{4}
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5a-4b=80
Multiply both sides of the equation by 20, the least common multiple of 4,5.
5a=80+4b
Add 4b to both sides.
5a=4b+80
The equation is in standard form.
\frac{5a}{5}=\frac{4b+80}{5}
Divide both sides by 5.
a=\frac{4b+80}{5}
Dividing by 5 undoes the multiplication by 5.
a=\frac{4b}{5}+16
Divide 80+4b by 5.
5a-4b=80
Multiply both sides of the equation by 20, the least common multiple of 4,5.
-4b=80-5a
Subtract 5a from both sides.
\frac{-4b}{-4}=\frac{80-5a}{-4}
Divide both sides by -4.
b=\frac{80-5a}{-4}
Dividing by -4 undoes the multiplication by -4.
b=\frac{5a}{4}-20
Divide 80-5a by -4.
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