x^2 - 81 = 0. Add 81 to each side.
x^2 = 81. Take the square root of each side.
x = 9, -9
Answer:
–9, 9
Explanation:
x² – 81 = 0
Add 81 to each side
x² – 81+81 = 0+81
x^2 = 81
Take the square root of each side
sqrt(x^2) = ± sqrt(81)
x = ± 9
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