I need 5A and 5B please Determine algebraically whether fx

I need 5A and 5B please.

Determine algebraically whether f(x) = squareroot 7x is a one-to-one function. Is the function graphed below one-to-one? Explain why or why not.

Solution

b) for a one to one function no two x values can have same y value

but here ther are same y values at 3 x values for some y values

so it is not a one to one function