Question 93220
start by multiplying by 2a ... 2as=2u(v-u)+a^2((v-u)/a)^2 ... the a^2 cancels leaving 2as=2u(v-u)+(v-u)^2


expanding gives 2as=2uv-2u^2+v^2-2uv+u^2 ... collecting terms gives 2as=-u^2+v^2 ... adding u^2 gives u^2+2as=v^2


it helps to know the answer, but the first step of multiplying by 2a would be done anyway to eliminate the fractions