Solve for a, b, c
a=20
b=15
c=5
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a=b+c a+b+c=40 b=3c
Reorder the equations.
b+c+b+c=40
Substitute b+c for a in the equation a+b+c=40.
b=20-c c=\frac{1}{3}b
Solve the second equation for b and the third equation for c.
c=\frac{1}{3}\left(20-c\right)
Substitute 20-c for b in the equation c=\frac{1}{3}b.
c=5
Solve c=\frac{1}{3}\left(20-c\right) for c.
b=20-5
Substitute 5 for c in the equation b=20-c.
b=15
Calculate b from b=20-5.
a=15+5
Substitute 15 for b and 5 for c in the equation a=b+c.
a=20
Calculate a from a=15+5.
a=20 b=15 c=5
The system is now solved.
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