I NEED HELPPP ASAPPP

For each expression use a property to write an equivalent expression.

If the ratio of sum of the first m and n terms of an ap is m2 : n2 , show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1).

Heather is riding a quadratic function that represents a parabola that touches but does not cross the x-axis at x=-6