Question

Доказать тождество 2(3-х)+7(х-4)-5(х-1)=3(х-4)-(3х+5)

Answer 1

2(3-х) + 7(х-4) - 5(х-1) = 3(х-4) - (3х+5),

6-2х + 7х-28 - 5х+5 = 3х-12 - 3х-5,

6 - 28 + 5 = -12 - 5,

-17 = -17 - тождество доказано