Question

3 раз прошу о помощи​

Answer 1

Ответ:

$1)\ \ 8(5y+3)^2+9(3y-1)^2=8(25y^2+30y+9)+9(9y^2-6y+1)=\\\\=281y^2+186y+81\\\\\\2)\ \ (2x-5)^2-2(7x-1)^2=4x^2-20x+25-2(49x^2-14x+1)=\\\\=-94x^2+8x+23\\\\\\3)\ \ (4y^2+3)^2+(9-4y^2)^2-2(4y^2+3)(4y^2-9)=\\\\=16y^4+24y^2+9+81-72y^2+16y^4-2(16y^4-24y^2-27)=144$

$4)\ \ (a^2-6ab+9b^2)(a^2+6ab+9b^2)-(a^2-9b^2)^2=\\\\=(a-3b)^2(a+3b)^2-(a-3b)^2(a+3b)^2=0$