SOLUTION: let F(x)=(x-9)^2 .Find x so that f(x)=20

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Question 373701: let F(x)=(x-9)^2 .Find x so that f(x)=20
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!



Hi,

F(x)=(x-9)^2

F(x)= x^2 - 18x +81

Find x so that f(x)= 20

20 =  x^2 - 18x +81

0  =  x^2 - 18x + 61

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+

x+=+%2818+%2B-+sqrt%28+80+%29%29%2F%282%29+

x+=+%2818+%2B-+sqrt%28+16%2A5+%29%29%2F%282%29+

x+=+%2818+%2B-+4sqrt%28+5+%29%29%2F%282%29+

x+=+%289+%2B-+2sqrt%28+5+%29%29