SOLUTION: Solve the equation by finding square roots. {{{ X^2+8x+16=9 }}} I got {{{ ( X^2 + 8X ) + 16 = 9 }}} - 9 - 9 ___________ ___________

Algebra ->  Radicals -> SOLUTION: Solve the equation by finding square roots. {{{ X^2+8x+16=9 }}} I got {{{ ( X^2 + 8X ) + 16 = 9 }}} - 9 - 9 ___________ ___________      Log On


   

Question 523319: Solve the equation by finding square roots.
+X%5E2%2B8x%2B16=9+
I got
+%28++X%5E2+%2B+8X++%29+%2B+16+=+9+
- 9 - 9
_______________________
+%28++x%5E2+%2B+8x+%29+%2B+7+%2B+16+=0+
+%28X%2B4%29%5E2+%2B+23=+0
- 23 - 23
____________________
+Sqrt+%28X+%2B+4+%29%5E2+=+-23+
X+4= sqrt -23
- 4 - 4
_______________
X +\- 4 + i sqrt 23
Is this right?
Found 2 solutions by Maths68, gsmani_iyer:
Answer by Maths68(1474) About Me  (Show Source):
You can put this solution on YOUR website!
+++x%5E2+%2B+8x+++%2B+16+=+9+
+++x%5E2+%2B+8x+++%2B+4%5E2+=+9+
+%28++x+%2B+4++%29%5E2+=+9+
+%28++x+%2B+4++%29%5E2+=+%283%29%5E2+
+sqrt%28%28++x+%2B+4++%29%5E2%29+=+sqrt%28%283%29%5E2+%29
+x+%2B+4+=+3
+x+=+3-4
+x+=+-1
Or
+x+%2B+4+=+-3
+x+%2B+4+=+-3-4
+x+%2B+4+=+-7
x= -7, -1

Answer by gsmani_iyer(201) About Me  (Show Source):
You can put this solution on YOUR website!
%28x%5E2%2B8x%2B16%29+=+9 Here you have to apply %28a%2Bb%29%5E2+=+a%5E2+%2B+2ab+%2B+b%5E2
x%5E2%2B2%2A4%2Ax%2B4%5E2+=+9 = %28x%2B4%29%5E2+=+9 Now taking out the square root both the sides we get,
x%2B4+=+3 Now subtracting 4 from both the sides, we get
x%2B4-4+=+3-4; So, x = -1.