In case an equation is in the form y′=f(ax+by+c), i. e., the RHS is a linear function of x and y. We will use the substitution v=ax+by+c to find an implicit general solution. The right hand side of the following first order problem y′=(5x−4y+4)3+54, y(0)=0 is a function of a linear combination of x and y, i. e., y′=f(ax+by+c) . To solve this problem we use the substitution v=ax+by+c which transforms the equation into a separable equation. We obtain the following separable equation in the variables x and v: v′= . Solving this equation an implicit general solution in terms of x, v can be written in the form x+ =C. Transforming back to the variables x and y we obtain an implicit solution x+ =C. Next using the initial condition y(0)=0 we find C= . Then, after a little algebra, we can write the unique explicit solution of the initial value problem as y=.