1
a) (a-4)²=а²-8а+16
b)(2y+8)²=4y²+32y+64
в) (5a-b)(5a+b)=5a²-b²
г)(x²+1)(x²-1)=x⁴-1
2
1)n²-0,64=(n-0,8)(n+0,8)
2)x²-12x+36=(x-6)²
3)y²+y+0.25=(y+0,5)²
3
(x+5)²-(x-3)(x+3) при=0.001
(0,001+5)²-(0,001-3)(0,001+3)=0,001²+2×0,001×5+5²-0,001²+3²=
=2×0,001×5+5²+3²=0,01+25+9=34,01
4
a) 2(7x-3y)(7x+3y)=2(49x²-9y²)=98x²-18y²
b)(a-6)²-(a+6)²=(a²-12a+36)-(a²+12a+36)=a²-12a+36-a²-12a-36=-24a