2x + y = 5 /*5
3x - 5y = 1
10x + 5y = 25
3x - 5y = 1
---------------- +
13x = 26
x = 2
y = 5 - 2x = 5 - 2*2 = 1
Ответ
(2; 1)
7xy^2-14x^2=7x(y^2-2x)
Так или нет?
(3x+4y)в квадрате - (4y-3x)в квадрате =
=((4y+3х)-(4y-3x))((4y+3х)+(4y-3x))=
=(4y+3х-4y+3x)(4y+3х+4y-3x)=6x*8y=48ху
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|x+1|>1,3
![\left \{ {{x+1\ \textgreater \ 1,3} \atop {-x-1\ \textgreater \ 1,3}} \right. \\ \\ x+1\ \textgreater \ 1,3 \\ x\ \textgreater \ 0,3 \\ \\ -x-1\ \textgreater \ 1,3 \\ -x\ \textgreater \ 2,3 \\ x\ \textless \ -2,3](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7Bx%2B1%5C+%5Ctextgreater+%5C+1%2C3%7D+%5Catop+%7B-x-1%5C+%5Ctextgreater+%5C+1%2C3%7D%7D+%5Cright.++%5C%5C++%5C%5C+x%2B1%5C+%5Ctextgreater+%5C+1%2C3+%5C%5C+x%5C+%5Ctextgreater+%5C+0%2C3+%5C%5C++%5C%5C+-x-1%5C+%5Ctextgreater+%5C+1%2C3+%5C%5C+-x%5C+%5Ctextgreater+%5C+2%2C3+%5C%5C+x%5C+%5Ctextless+%5C+-2%2C3)
Ответ: x∈(-∞;-2,3)U(0,3;+∞)