Ответ:
Пошаговое объяснение:
1) 5(x-3) = 2(4x-3) + 2x
5x-15 = 8x-6+2x
-15+6 = 8x+2x-5x
-9 = 5x
x = -9/5
2) 3(x-4)+2(5x-3) = 7x+4
3x-12+10x-6 = 7x+4
3x+10x-7x = 4+12+6
6x = 22
x = 22/6
3) 21(x-5)-3(x-2) = 4(5x-4)
21x-105-3x+6 = 20x-16
21x-3x-20x = -16-6+105
-2x = 83
x = -83/2
4) 50 * 60 / 100 = 30
50+30 = 80
80 * 20 / 100 = 16
80-16=64
Ответ: 64