1.) Solve for x using the Square Root Property:
x^2 + 5 = 86
-9
9
-9, 9
2.) x^2 - 8 = 13
-√21, √21
-√21
-3, 7
Two problems, help please?
2009-08-04 4:34 pm
回答 (5)
2009-08-04 4:49 pm
✔ 最佳答案
1.) x^2 + 5 = 86 x^2=86-5
X^2=81
x=±√(81)
x=9,-9 answer//
2.) x^2 - 8 = 13
x^2=13+8
x^2=21
x=±√21
x=-√21,√21 answer//
2009-08-05 1:32 am
1)
x^2 + 5 = 86
x^2 = 86 - 5
x = 屉81
x = ±9
2)
x^2 - 8 = 13
x^2 = 13 + 8
x = 屉21
x^2 + 5 = 86
x^2 = 86 - 5
x = 屉81
x = ±9
2)
x^2 - 8 = 13
x^2 = 13 + 8
x = 屉21
2009-08-04 11:41 pm
9 & â21
2009-08-04 11:40 pm
1)
x^2 + 5 = 86
x^2 = 81
x = 9, -9
2)
x^2 - 8 = 13
x^2 = 21
x = sqrt(21), -sqrt(21)
Where did those -3 and 7 come from? 3 =/= sqrt(21), 7 =/= sqrt(21).
x^2 + 5 = 86
x^2 = 81
x = 9, -9
2)
x^2 - 8 = 13
x^2 = 21
x = sqrt(21), -sqrt(21)
Where did those -3 and 7 come from? 3 =/= sqrt(21), 7 =/= sqrt(21).
2009-08-04 11:39 pm
x² + 5 = 86
Isolate x² by subtracting 5 from both sides.
x² = 81
Take square root of both sides.
x = ± â81
x = ± 9
x² - 8 = 13
Isolate x² by adding to both sides.
x² = 21
Take square root of both sides.
x = ± â21
Isolate x² by subtracting 5 from both sides.
x² = 81
Take square root of both sides.
x = ± â81
x = ± 9
x² - 8 = 13
Isolate x² by adding to both sides.
x² = 21
Take square root of both sides.
x = ± â21
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