SOLUTION: Could you please help me with this problem Solve {{{ -6 (x+5)^2=120 }}}

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Question 19945: Could you please help me with this problem


Solve +-6+%28x%2B5%29%5E2=120+
Answer by longjonsilver(2297) About Me  (Show Source):
You can put this solution on YOUR website!
straight away, you should have warning bells ringing, since +-6+%28x%2B5%29%5E2=120+ can be altered to %28x%2B5%29%5E2=-20.

From this point, we need to take square roots of both sides, to remove the squared term on the left. However, we then have sqrt%28-20%29, which has no real solution. You then enter into Complex numbers and i am not sure you have done this topic.

Anyway, here goes:

x%2B5+=+sqrt%28-20%29
x%2B5+=+sqrt%28-1%2A4%2A5%29
x%2B5+=+sqrt%28-1%29sqrt%284%29sqrt%285%29
x%2B5+=+i%2Asqrt%284%29sqrt%285%29
x%2B5+=+i%2A2%2Asqrt%285%29
x%2B5+=+2sqrt%285%29i

--> x+=+2sqrt%285%29i+-+5

jon.