1. .........=4а²+ 24а+9 - 8а² +2а +3=26а - 4а²+3
2.
а) ....=7с²(а² -4b²)=7c²(a-2b)(a+2b)
б) ....=5(а² - 6ab+9b²)=5(a-3b)(a-3b)=5(a-3b)²
3.
y=kx+b
M (0; -12)
-12=k*0+b
b= -12
K ( -3;0)
0=-3k+b
3k= -12
k= -4
b= -12, k= -4
4.
7х-у=10 ( *2)
5х+2у= -1
14х-2у=20
5х+2у= -1
19х=19
7х -у=10
х=1
у=7х-10
х=1
у= -3
(1; -3)