Algebrahard · Past Paper
If 5/(x+y) + 1/(x-y) = 2 and 15/(x+y) - 5/(x-y) = -2, find x+y.
A5
B2
C10
D1
✓ Correct Answer: A — 5
Let u=1/(x+y), v=1/(x-y). 5u+v=2, 15u-5v=-2. Solving gives u=1/5 -> x+y=5.
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✓ Correct Answer: A — 5
Let u=1/(x+y), v=1/(x-y). 5u+v=2, 15u-5v=-2. Solving gives u=1/5 -> x+y=5.
Share this question