Ответ:
1) x = 4;
2) x = 1
Пошаговое объяснение:
1) (4х - 1) - (3х + 1) = 2
4x - 1 - 3x - 1 = 2
x - 2 = 2
x = 2 + 2 = 4
2) (20х - 5) - (4 + 7х) = 4
20x - 5 - 4 - 7x = 4
13x - 9 = 4
13x = 4 + 9
13x = 13
x = 13/13 = 1
(4+b)³-b²(b+12)=4³+3*4²b+3*4b²+b³-b³-12b²=4³+3*4²b=4²(4+3b)=16(4+3b)
При b=-1.5
16(4+3b)=16(4-4.5)=-8
Ответ: 16(4+3b); -8