SOLUTION: x4 − 7x2 − 144 = 0 find all real solutions algebraically

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Question 668118: x4 − 7x2 − 144 = 0 find all real solutions algebraically
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
x^4 − 7x^2 − 144 = 0
use the quadratic formula
x%5E2+=+%28-%28-7%29+%2B-+sqrt%28-7%5E2-4%2A1%2A-144+%29%29%2F%282%2A1%29+
:
x%5E2+=+%287+%2B-+sqrt%2849%2B576+%29%29%2F2+
:
x%5E2+=+%287+%2B-+sqrt%28625+%29%29%2F2%29+
two solutions
x%5E2+=+%287+%2B+25%29%2F2+
x^2 = 32%2F2
x^2 = 16
x = +4, -4
and
x%5E2+=+%287+-+25%29%2F2+
x^2 = -18%2F2
Non-real solutions
:
Real solutions: x=4, x=-4