Question

Which equation is the inverse of y = 7x2 – 10?

Answer 1

we have

$y=7x^{2}-10$

To find the inverse

Step 1

Exchanges the variables, x for y and y for x

$x=7y^{2}-10$

Step 2

Isolate the variable y

$x=7y^{2}-10$

$7y^{2}=x+10$

$y^{2}= \frac{x+10}{7}$

Square Root both sides

$y=(+/-)\sqrt{\frac{x+10}{7}}$

Step 3

Let

$f(x)^{-1}=y$

so

$f(x)^{-1}=(+/-)\sqrt{\frac{x+10}{7}}$

therefore

the answer is

The inverse is  

$f(x)^{-1}=(+/-)\sqrt{\frac{x+10}{7}}$

Answer 2

Y=±√x+10
       --------
           7 
and that is the inverse of y=7x2-10