5/7*(0,21-1,4х)-4/9*(0,36-4,5х) = 1
0,15-1х - 0,16+2х = 1
2х-1х = 1-0,15+0,16
х = 1,01
5/7*(0,21-1,4*1,01)-4/9*(0,36-4,5*1,01)= 5/7*(-1,204)- 4/9*(-4,185) = -0,86+1,86 = 1
Ответ: 1,01.
5/7*21/100+5/7*(-14/10х)-4/9*36/100-4/9*(-45/10х) = 1
5/7*21/100+5/7*(-7/5х)-4/9*9/25-4/9*(-9/2х) = 1
3/20-х-4/25+2х = 1
2х-х = 1+4/25-3/20
х = 29/25-3/20
х = 116/100-15/100
х = 101/100
х = 1 1/100
Ответ: 1 1/100.