Answer
See explanations.
Work Step by Step
Step 1. Use the previous results in the Pythagorean theorem, we have $(x_1^2+m_1^2x_1^2)+(x_2^2+m_2^2x_2^2)=(x_2-x_1)^2+(m_2x_2-m_1x_1)^2$
Step 2. Cancel some items from each side, we have $0=-2x_1x_2-2m_1m_2x_1x_2$ or $-2m_1m_2x_1x_2-2x_1x_2=0$
