Пошаговое объяснение:
1)
4/7 (х-1) = 2/7 + х
4/7х - 4/7 = 2/7 + х
4/7х - х = 2/7 + 4/7
-3/7х = 6/7
х = 6/7 : (-3/7)
х = 6/7 * (-7/3)
х = -6/3
х = -2
2)
4. 5/9 - 1/6х = 5(1 + 0,1х)
4. 5/9 - 1/6х = 5 + 0,5х
-1/6х - 0,5х = 5 - 4. 5/9
-1/6х - 5/10х = 4. 9/9 - 4. 5/9
-5/30х - 15/30х = 4/9
-20/30х = 4/9
-2/3х = 4/9
х = 4/9 : (-2/3)
х = 4/9 * (-3/2)
х = -12/18
х = -2/3
3)
5(х - 1,5) = 4. 2/3х - 8. 3/14
5х - 7,5 = 4. 2/3х - 8. 3/14
5х - 4. 2/3х = -8. 3/14 + 7,5
4. 3/3х - 4. 2/3х = -8. 3/14 + 7. 5/10
1/3х = -8. 3/14 + 7. 1/2
1/3х = -8. 3/14 + 7. 7/14
1/3х = -7. 17/14 + 7. 7/14
1/3х = -10/14
1/3х = -5/7
х = -5/7 : 1/3
х = -5/7 * 3/1
х = -15/7
х = -2. 1/7
4)
1. 7/9х - 1. 1/9 = 4. 2/9(1 - х)
1. 7/9х - 1. 1/9 = 4. 2/9 - 4. 2/9х
1. 7/9х + 4. 2/9х = 4. 2/9 + 1. 1/9
5. 9/9х = 5. 3/9
6х = 5. 1/3
х = 5. 1/3 : 6
х = 16/3 * 1/6
х = 16/18
х = 8/9
90/45=2
90/30=3
90/15=6
ответ:90