Onto function

[mathproblems]

f(x)=4x³ -1
x³ = (y+1)/4
x= ((y+1)/4) <sup>1/3

is this correct?
Thank you.</sup>

 

[srmichael]

f(x)=4x³ -1
x³ = (y+1)/4
x= ((y+1)/4) <sup>1/3

is this correct?
Thank you.</sup>

Not sure what an "onto" function is, but, yes, you solved for x correctly.