Answer:
x = (c+a)/2
y = (c-a)/2
Step-by-step explanation:
Add the two equations and you get ...
(x +y) +(x -y) = (c) +(a)
2x = c+a
x = (c+a)/2
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Subtract the second equation from the first and you get ...
(x +y) -(x -y) = (c) -(a)
2y = c-a
y = (c-a)/2
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Comment on this problem
This is what I call a "sum and difference" problem. The solution shown here is (obviously) the generic solution to such a problem. Remembering this can get you quickly to the answer any time you're given the sum of two unknowns and their difference.
