X1=9- корень305/7
х2=4/3
х3=9+корень305/7
8х+10=0
8х=-10
х=10/8
х=-1.25
Ответ: -1.25
A₁ = a₁₄ - d * (n - 1) = -57 + 3 * 13 = -18
a₃ = a₁ + d * (n - 1) = -18 - 3 * 2 = -24
-11а-11б=-11(а+б)=-11*12=-132
3a^2+6ab+3b^2=(3a+3b)^2=36^2=1296
-10a^2-10b^2-20ab / * (-1)
10a^2+10b^2+20ab=(10a+10b)^2=120^2=144