SOLUTION: solve the equation by making a substituition x-(7*x^.5)+8 =0

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Question 62564: solve the equation by making a substituition
x-(7*x^.5)+8 =0
Answer by 303795(602) About Me  (Show Source):
You can put this solution on YOUR website!
x-%287%2Ax%5E.5%29%2B8+=0
Make the substitution y=sqrt%28x%29
The problem now becomes
y%5E2-7%2Ay%2B8+=0
Use the quadratic formula with a=1 b=-7 and c=8.
y+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
y+=+%28-%28-7%29+%2B-+sqrt%28+%28-7%29%5E2-4%2A1%2A8+%29%29%2F%282%2A1%29+
y+=+%287+%2B-+sqrt%28+49-32+%29%29%2F2+
y+=+%287+%2B-+sqrt%28+17%29%29%2F2+
y+=+%287+%2B+sqrt%28+17%29%29%2F2+ or y+=+%287+-+sqrt%28+17%29%29%2F2+

Use your calculator to find each of the values for y. Remembering that y=sqrt%28x%29 you would then square each of the y values to find the two possible values for x.