Question 86765
x^2 + 4x + 4 = 7
x^2 + 4x + 4-7 = 7-7
x^2 + 4x -3=0
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{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
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{{{x = (-4 +- sqrt( 4^2-(4)(1)(-3) ))/(2*1) }}}
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{{{x = ((-4 +- sqrt( 16+12) ))/(2) )}}}
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{{{x = ((-4 +- sqrt( 28) ))/(2) )}}}
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{{{x = ((-4 +- 2sqrt(7) ))/(2) )}}}
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{{{x = ((2)-2 +- 1sqrt(7) ))/(2) )}}} [factor out a (2)
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{{{x = ((1)-2 +- 1sqrt(7) ))/(1) )}}} [cancel out]
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{{{x = (-2 +- sqrt(7) )) )}}}[this form is acceptable for the final answer, but be sure to check your answer]
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check by plugging the x's back into the orginal formula and solving.
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{{{x = (-2 + sqrt(7) )) )}}}
x= 0.64575

x^2 + 4x + 4 = 7

(0.64575)^2 + 4(0.64575) + 4 = 7
6.999 = 7 [close enough]

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and
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{{{x = (-2 - sqrt(7) )) )}}}
x=-4.6457
(-4.6457)^2 + 4(-4.6457) + 4 = 7
6.999 = 7 [also, close enough]
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