Выполните умножение: 1) (2a²-3b)(a²+2ab+5b²) 2) (x²-2xy)(x²-5xy+3y²) 3)...

Решите задачу:

$1) (2a^2-3b)(a^2+2ab+5b^2)= \\ =2a^4+4a^3b+10a^2b^2-3a^2b-6ab^2-15b^3 \\ 2)( x^{2} -2xy)( x^{2} -5xy +3y^2)= \\ =x^4-5x^3y+3x^2y^2-2x^3y+10x^2y^2-6xy^3= \\ =x^4-7x^3y+13x^2y^2-6xy^3 \\ 3)(x-y)(x^3+x^2y-xy^2+y^3)= \\ =x^4+x^3y-x^2y^2+xy^3-x^3y+x^2y^2-xy^3+y^4= \\ =x^4+x^3y-x^3y+y^4 \\ 4)(a+b)(a^3-a^2b+ab^2-b^3)= \\ =a^4-a^3b+a^2b^2-ab^3+a^3b-a^2b^2+ab^3-b^4= \\ =a^4-a^3b+a^3b-b^4$

$(x-4)(x-2)-(x-1)(x-3)= \\ =x^{2} -2x-4x+8-( x^{2} -3x-x+3)= \\ =x^{2} -2x-4x+8- x^{2} +3x+x-3= \\ =-2x+5=-2*1 \frac{3}{4}+5=- \frac{2}{1}* \frac{7}{4}+5=-3,5+5=1,5$

$1)a x^{2} -b x^{2} -bx+ax-a+b= \\ = x^{2} (a-b)+x(a-b)-(a-b)= \\ =(a-b)( x^{2} +x-1) \\ \\ 2)a x^{2} +b x^{2} +ax-c x^{2} +bx-cx= \\ = x^{2} (a+b-c)+x(a+b-c)= \\ =(a+b-c)( x^{2} +x)= \\ =(a+b-c)x(x+1)= \\ =x(x+1)(a+b-c)$