Solve for a
a=420-b
Solve for b
b=420-a
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a+b=210\times 2
Multiply both sides by 2.
a+b=420
Multiply 210 and 2 to get 420.
a=420-b
Subtract b from both sides.
a+b=210\times 2
Multiply both sides by 2.
a+b=420
Multiply 210 and 2 to get 420.
b=420-a
Subtract a from both sides.
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