A)V=Sh/3
S=3V/h
h=3V/S
б)V=2m³*140/3=280m³/3см³
в)S=3*45/4=33,75дм³
1м=10дм
1) 4a^2-1-(4a+2)-4a
4a^2-1-4a-2-4a
4a^2-8a-3
1+8+3=12
2) (a+b)^2-2ab=a^2-b^2
a^2+2ab+b^2-2ab=a^2+b^2
a^2+b^2=a^2+b^2
- 2.24 = X^2 + 3AX + 0.01
X^2 + 3AX + 2.25 = 0
D = 9 - 4*1*2.25 = 9 - 9 = 0
X = - 3 \ 2 = - 1.5
......................
2.25 - 4.5A + 2.25 = 0
-4,5 A = - 4.5
A = 1
...................................
ответ: при А = 1
Решение на фото//////////
4.2x + 17.2 - 8.4 + 2.8x = -5.4
7x = -14.2
x = -14.2/7