№2
1)(2d+7)²-5d(6+3d)=4d²+28d+49-30d-15d²=-11d²-2d+49=
= 11d²+2d-49
2)(x-4)(x+4)-(x-3)²=x²-16-x²+6x-9=6x-25
3)y²(2y-3)(2y+3)-4(y²-6y)²-6y²(3+8y)=
=y²(4y²-9)-4(y^4-12y³+36y²)-18y-48y³=
4y^4-9y²-4y^4+48y³-144y²-18y-48y³=-153y²
№3(k-3)²+(6-2k)(6+2k)=k²-6k+9+36-4k²=45-6k-3k²/(-3)=
=k²+2k-15 при k=1.5
2.25+3-15= -9.75
№4 1) 4p²-625d²=(2p-25d)(2p+25d)
2) 49a^8-4b^4=(7a^4-2b²)(7a^4+2b²)
3) 9a²+30a+25=(3a+5)²
4) -7a²-14ab-7b²=-(√7a+√7b)²
5) (6-x)²+3(6-x)=36-12x+x²+18-3x=x²-15x+54