SOLUTION: four times the square root of the quantity of 3a+4 equals a+13. I know the answers are 7 and 15 but cannot figure out how to get them algebraically
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Question 308442: four times the square root of the quantity of 3a+4 equals a+13. I know the answers are 7 and 15 but cannot figure out how to get them algebraically
Found 2 solutions by stanbon, JBarnum:
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
four times the square root of the quantity of 3a+4 equals a+13. I know the answers are 7 and 15 but cannot figure out how to get them algebraically
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4(sqrt(3a+4)) = a+13
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Square both sides to get:
16(3a+4) = a^2+26a+169
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48a+64 = a^2+26a+169
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a^2 - 22a + 105 = 0
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(a-15)(a-7) = 0
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a = 15 or a = 7
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Cheers,
Stan H.
Answer by JBarnum(2146) (Show Source): You can put this solution on YOUR website!
square everything
distribute
subtract 48a and 64 from both sides
-7 and -15 both multiply to get +105 and add to get -22
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