X(2х-1)-(6+х)(х-6)+(х+10)(10-х) = x(2х-1)-(х+6)(х-6)+(10+х)(10-х ) =
= 2х²-х-х²+36+100-х²=136-х
х=-101
136-(-101)=136+101=237
S₁₁ = (a₁ + a₁₁)*11/2
22 = (a₁ + 92)*11/2
a₁ + 92 = 4
a₁ = -88
a₁₁ = a₁ + 10d
92 = -88 + 10d
10d = 180
d = 18
1) =b/3
2) =7c/6y
3) =25c/18a
4)=7p/12x
5)=c/5b
6)=6/5
7)=2y/3a
8)=7y/6c
9)-4x/30y
10)=-4y/7x
11)=2a/3b
12)=2/-3c
Обе части домножить на 88 тогда
11х +8х=-152
19х=-152
х=-152:19
х=-8