-0.5÷7/8x(-5/4);原式=?(-7)÷(-3/2)÷(-7/5);XX=?3又1/3÷(-2又1/3)÷(-1又1/5);XX=?1÷[(-1)÷4/5];XX=?(-2/3)x8/27x(-1.5)÷(-16/9);XX=?(-36)÷(-1又2/1)x(-2/3);XX=?(-2/3)x(-8/5)÷(-0.25);XX=?x=乘,乘号不会打所以用英文x来作用。。。这几题, !!大哥求解!!!!!!!!!!!!!!!!!!!!!!!