Solve for a, b, c
a=20
b=60
c=100
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b=3a a+b+c=180 c=5a
Reorder the equations.
a+3a+c=180
Substitute 3a for b in the equation a+b+c=180.
a=-\frac{1}{4}c+45
Solve a+3a+c=180 for a.
c=5\left(-\frac{1}{4}c+45\right)
Substitute -\frac{1}{4}c+45 for a in the equation c=5a.
c=100
Solve c=5\left(-\frac{1}{4}c+45\right) for c.
a=-\frac{1}{4}\times 100+45
Substitute 100 for c in the equation a=-\frac{1}{4}c+45.
a=20
Calculate a from a=-\frac{1}{4}\times 100+45.
b=3\times 20
Substitute 20 for a in the equation b=3a.
b=60
Calculate b from b=3\times 20.
a=20 b=60 c=100
The system is now solved.
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