1)(a-b)(a+b+2)-(a-b)(a-b-2)=(2b+2)(a-b)
2)b²+ab-a²-b+a=(b-a)(b+a)+a(b-a)-(b-a)=(b-a)(b+a+a-1)=(b-a)(b+2a-1)
3)<span>a(a+2)+b(b-2)-2(a+1)(b+1)+1=a</span>²-2ab+b²-4b-1
D = b²-4ac = 23²-4•120 = 529-480 = 49
x = 23±7/2
x1 = 30/2 = 15
x2 = 8
<span>5a (4a + b)
</span><span>4 + ( 3 - 7 )
</span><span>6c - 2a </span>
Х^2-8х=0
х(х+8)=0
х=0
х+8=0, х=-8
Ответ: (0;-8)