Ответы и объяснения

2016-09-12T07:56:57+03:00
1) 13x + 12x + 15 = 240
25x + 15 = 240
25x = 240 - 15
25x = 225
x = 225/25
x = 9

2) (14x - 2x)/17 = 312
12x/17 = 312
12x = 312*17
12x = 12*26*17
x = 26*17 
x = 442