I need to apply the ralston 2nd order method to find an approximate value for y(2) of the following differential equation:

xy'' - y' = x^2 + x

With initial conditions y(1) = 1 and y'(1) = 5

So far I have done z1=y, z2=y' and z3=y'', resulting in the equation

xz2' = x^2 + x + z2

This equation finds an approximate value for y'(x), but I need a value for y(x) how can I advance from this?