Кто что сможет,пожалуйста!

$2) x^{2}-y^{2}- x^{2}+3y^{2}=2y^{2}$

3) $16y^{2}-0.25=(4y-0.5)(4y+0.5) \\ a^{2}+10ab+25b^{2}=(a+5b)^{2}$

4) $25-10x+x^{2}-2.5x-x^{2}=0 \\ 25-12.5x=0 -12.5x=-25 x=2$

5) $a) (2a-b^{2})(2a+b^{2})=4a^{2}-b^{4} \\ b) (x-6x^{3})^{2}=x^{2}-12^{4}+36x^{6}\\ c) (y+b)^{2}(y-b)^{2}=(y+b)(y+b)(y-b)(y-b)=\\=(y-b)(y+b)(y-b)(y+b)=(y^{2}-b^{2})(y^{2}-b^{2})=\\=y^{4}-b^{2}y^{2}-b^{2}y^{2}-b^{4}=y^{4}-2b^{2}y^{2}-b^{4}$