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4 votes
(4x+7)^2=60 how to do extracting the square root?

1 Answer

7 votes
(4x + 7)² = 60
(4x + 7)(4x + 7) = 60
(4x² + 28x + 28x + 49) = 60
4x² + 56x + 49 = 60
-49 -49
4x² + 56x = 11
4x² + 56x - 11 = 11 - 11
4x² + 56x - 11 = 0
x = -56 +/- √(56² - 4(4)(-11))
2(4)
x = -56 +/- √(3136 + 88)
8
x = -56 +/- √(3174)
8
x = -56 +/- 56.34
8
x = -7 +/- 7.0425
x = -7 + 7.70425 x = -7 - 7.70425
x = 0.70425 x = -14.70425
User Mark Dickinson
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