Плиз помогите. Дам 99 баллов)))

1.
1)
$a^2+(3a-b)^2=a^2+(9a^2-6ab+b^2)=10a^2-6ab+b^2\\\\9b^2-(a-3b)^2=(3b-(a-3b))(3b+(a-3b))=\\=(6b-a)a=-a^2+6ab\\\\(5a+7b)^2-70ab=25a^2+70ab+49b^2-70ab=25a^2+49b^2\\\\(8a-b)^2-64a^2=(8a-b-8a)(8a-b+8a)=-b(16a-b)=\\=-16ab+b^2$

2)
$(5+y)^2+y(y-7)=25+10y+y^2+y^2-7y=2y^2+3y+25\\\\a(4-a)+(4-a)^2=(4-a)(4-a+a)=4(4-a)=-4a+16\\\\(x-8)^2-2x(6-x)^2=(x^2-16x+64)-(2x^3-24x^2+72x)=\\=-2x^3+25x^2-88x+64\\\\(c+7)c-(1-c)^2=c^2+7c-c^2+2c-1=9c-1$

3)
$2(a-b)^2=2a^2-4ab+2b^2\\\\a(1+2a)^2=4a^3+4a^2+a\\\\-6(2x-y)^2=-24x^2+24xy-6y^2\\\\-y(3x-y)^2=-9x^2y+6xy^2-y^3$

2.
1)
$(a-3b)^2+(a+3b)^2=a^2-6ab+9b^2+a^2+6ab+9b^2=\\=2a^2+18b^2\\\\(x+2y)^2-(x-2y)^2=(x+2y-x+2y)(x+2y+x-2y)=4y*2x=\\=8xy$

2)
$(a+b)^2-2ab=a^2+b^2\\(a^2+b^2)^2-2a^2b^2=a^4+b^4\\(a^4+b^4)^2-2a^4b^4=a^8+b^8\\(a^8+b^8)^2-2a^8b^8=a^{16}+b^{16}\\$

3.
1)
$(3a+4b)^2+(3a-2b)8b=9a^2+24ab+16b^2+24ab-16b^2=\\=9a^2+48ab=3a(3a+16b)$

2)
$(6a-2)^2-(5a+2)^2=36a^2-24a+4-25a^2-20a-4=\\=11a^2-44a=11a(a-4)$

4.
$(a+3)^2=a^2+39\\a^2+6a+9=a^2+39\\6a=30\\a=5$