Question 1025903
Find f −1. 
f(x) = x^2 + 9 for x ≥ 0
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Interchange x and y::
x = y^2+9 for y >= 0
Solve for "y"::
y = sqrt(x-9) for y >= 9
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{{{graph(400,400,-10,20,-10,10,sqrt(x-9))}}}
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Cheers,
Stan H.