Ответ:
3(1+x)/5 = - 9
3(1+x) = -(5 × 9)
3 + 3x = -45
3x = -45 - 3
3x = -48
x = -48/3
x = -16
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2(3z-4) = 5(z+1)
2(3z-4) = 5z
3z-4 = 5z : 2
3z-4 = 4,1z
3z = 4,1z + 4
3z = 8,1z
z = 8,1z : 3
z = 2,3z