先算分母,
120/(X-V)+120/(X+V)
=[120(X+V)+120(X-V)]/(X-V)(X+V) (通分,分母为(X+V)(X-V))
=240X/(X^2-V^2)
再算整个式子:
(除以一个数等于乘以这个数的倒数)
V=288(X^2-V^2)/240X
V=6(X^2-V^2)/5X
5XV=6X^2-6V^2
6X^2-5XV-6V^2=0
(3X+2V)(2X-3V)=0
所以3X=-2V或2X=3V
X=-2V/3或X=3V/2