If `f(x)=sqrt(7x+2)`, which expression represents f^-1(x)? (Here: `x>=-(2)/(7)`) A. ` 1/(sqrt(7x+2)) `
B. ` (x^2+2)/7 `
C. ` (y^2-2)/7 `
D. ` (x^2-2)/7 `

Help!

Anyone know? will mark brainliest if you're correct!

What is the base of 1/9 to the power of 2

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed