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September 1, 2014

September 1, 2014

Posted by **cheyanne** on Tuesday, March 6, 2012 at 12:19am.

1) (/3x+7) = x-1

2) (3/2x)-3=9

Note: (/3x+7) is the square root of 3x plus 7 and (3/2x)-3=9 is 3 times the square root of 2x - 3 equals 9.

- math -
**Henry**, Wednesday, March 7, 2012 at 11:40am1. sqrt(3x+7) = x-1.

Square both sides:

3x + 7 = x^2 - 2x + 1.

-x^2 + 2x +3x = 1 - 7 = - 6.

Multiply both sides by -1:

x^2 -2x -3x = 6.

x^2 - 5x - 6 = 0.

(x+1)(x-6) = 0.

x+1 = 0.

X = -1. Does not satisfy original Eq.

x-6 = 0.

X = 6.

2. 3*sqrt(2x) - 3 = 9.

3*sqrt(2x) = 9+3 = 12.

Divide both sides by 3:

sqrt(2x) = 4.

Square both sides:

2x = 16.

X = 8.

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