find the value/s of x:
3(x+3) + (sq root of x+3) = 2
You have to think :
How to eliminate the sq root...!
Write :
(sq root of x+3) = 2 - 3(x+3)
x + 3 = (2 - 3x - 9)^2
x + 3 = (-3x -7)^2
x + 3 = 9x^2 + 42x + 49
0 = 9x^2 + 41x + 46
Now use the quadratic equation to find x.
3x + 9 + sqrt(x+3) = 2
sqrt(x+3) = -3x - 7
x + 3 = (-3x - 7)²
x + 3 = 9x² + 42x + 49
9x² + 41x + 46 = 0
-41 +/- sqrt(41² - 4(9)(46))
---------------------------------
18
-41 +/- sqrt(25)
-----------------------
(-41 +/- 5) / 18
x = -46/18 or -36/18 = -23/9 or -2
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Verified answer
You have to think :
How to eliminate the sq root...!
Write :
(sq root of x+3) = 2 - 3(x+3)
3(x+3) + (sq root of x+3) = 2
(sq root of x+3) = 2 - 3(x+3)
x + 3 = (2 - 3x - 9)^2
x + 3 = (-3x -7)^2
x + 3 = 9x^2 + 42x + 49
0 = 9x^2 + 41x + 46
Now use the quadratic equation to find x.
3x + 9 + sqrt(x+3) = 2
sqrt(x+3) = -3x - 7
x + 3 = (-3x - 7)²
x + 3 = 9x² + 42x + 49
9x² + 41x + 46 = 0
-41 +/- sqrt(41² - 4(9)(46))
---------------------------------
18
-41 +/- sqrt(25)
-----------------------
18
(-41 +/- 5) / 18
x = -46/18 or -36/18 = -23/9 or -2