Question

人教版数学七年级下第八章总复习题答案

Answer 1

设从甲地到乙地上坡为Xkm,平路为Ykm,下坡为Zkm,则 X+Y+Z=3.3 ① X/3 + Y/4 + Z/5 = 51/60 ② Z/3 + Y/4 + X/5 = 53.4/60 ③ 由②式得到20X+15Y+12Z=51 ④ 由③式得到20Z+15Y+12X=53.4 ⑤ 由⑤式-④式得到Z-X=0.3,那...