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If 2x2 + 8y = 121.5 and x2 - 8y = 121.5, then x =
5 months ago
Q:
If 2x2 + 8y = 121.5 and x2 - 8y = 121.5, then x =
Accepted Solution
A:
2x² +8y = 121.5
8y = 121.5 - 2x²
and,
x²-8y = 121.5
-8y = 121.5 -x²
8y = x²-121.5
Now, equate the two 8y's
121.5-2x² = x² -121.5
-3x² = -121.5-121.5
-3x² = -243
3x² = 243
x² = 81
x = ±9