6f+2-4f-8
2x multiplied by -x
2x - x
y^3 + ay + a^3
find roots where a>0.
find roots
solve 4ux + uy = 3u, given u=3e^-y -e^-5y then x = 0 in method of separation of variables
y^3 + 5y + 125
solve r + 2 + = 7
3x - 2x
