Помогите решить y=100x+5 y=20x+180 y=минус 7x+21 y=-7-21
1) y = 100x + 5
y = 20x + 180
2) y = -7x + 21
y = -7 - 21 = -28
2) -28 = -7х + 21
7x = 21 + 28 = 49
x = 7
1) 100x + 5 = 20x + 180
100x - 20x = 180 - 5
80x = 175
x = 175\80
x = 2целых3\16
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