Algebrahard · Past Paper
If 2^x + 3^y = 17 and 2^(x+1) - 3^y = 7, find x.
A3
B2
C4
D1
✓ Correct Answer: A — 3
Let u=2^x, v=3^y. u+v=17, 2u-v=7. Adding gives 3u=24 -> u=8 -> 2^x=8 -> x=3.
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✓ Correct Answer: A — 3
Let u=2^x, v=3^y. u+v=17, 2u-v=7. Adding gives 3u=24 -> u=8 -> 2^x=8 -> x=3.
Share this question