а)
8,9х+17,54=5,4х+2,84
8,9x-5,4x=2,84-17,54
3,5x=-14,7
x=-14,7:3,5
x= -4,2
б)
3*(5-х)+13=4*(3х-8)
15-3x+13=12x-32
28-3x=12x-32
12x+3x=28+32
15x=60
x=60:15
x=4
в)
3/7 - 1/4х=5 3/7-4х
-1/4x + 4x =5 3/7 - 3/7
3 3/4x = 5
x=5 : 3 3/4
x=5 : 15/4
x=5 * 4/15
x= 4/3
x= 1 1/3