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If y = 3x2 - 9, what is its inverse?

User Mludd
by
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1 Answer

2 votes

Answer:

f^-1(x) = √((y +9)/3)

Explanation:

You want the inverse function of y = 3x² -9.

Inverse function

The given relation will only have an inverse function if its domain is restricted to values x ≥ 0.

We can find that inverse function by interchanging the variables x and y, then solving for y:

x = 3y² -9

x +9 = 3y² . . . . . . . add 9

(x +9)/3 = y² . . . . . . divide by 3

y = √((x+9)/3) . . . . . take the square root

The inverse function is f^-1(x) = √((x +9)/3).

User Danny Mor
by
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