1. а)25x²y⁴-49=(5xy²-7)(5xy²+7;
б)9k¹⁰-1/36=(3k⁵-1/6)(3k⁵+1/6);
в)(8t²-2)-16t⁴=(√(8t²-2)-4t²)(√(8t²-2) +4t²);
г)(2d+3c)²-9c²-6cd-d²=4d²+12cd+9c²-9c²-6cd-d²=3d²+6cd=3d(d+2c);
2.49y²+14y+1=25;
49y²+14y-24=0;
y₁,₂=[-14⁺₋√(14²+4·49·24)]/2·49=[-14⁺₋√4900]/98=(-14⁺₋70)/98;
y₁=(-14-70)/98=-84/98=-0.8571;
y₂=(-14+70)/98=0.5714;
3.a⁴b⁴-a⁴+6a²b²-9b⁴=a⁴b⁴-(a⁴-6a²b²+9b⁴)=a⁴b⁴-(a²-3b²)²=
=(a²b²+a²-3b²)(a²b²-a²+3b²);