Question

решите пожалуйста дам 35 баллов​

Answer 1

$1)\ \ a)\ \ (a-3b)(a+3b)-(a-3b)^2=a^2-9b^2-(a^2-6b+9b^2)=-18b^2+6b=\\\\=6b\cdot (1-3b)\\\\b)\ \ 4x^3\cdot (-2x^2)^3=4x^3\cdot (-8x^6)=-32x^9\\\\c)\ \ (-4ab^3)^2=16a^2b^6\\\\\\2)\ \ a)\ \ 81x^3-x=x(81x^2-1)=x(9x-1)(9x+1)\\\\b)\ \ 3y^2-30y+75=3\cdot (y^2-10y+25)=3\cdot (x-5)^2\\\\c)\ \ x-y-2x^2+2y^2=(x-y)-2(x^2-y^2)=\\\\=(x-y)-2\, (x-y)(x+y)=(x-y)\cdot (1-2\, (x+y))=(x-y)\cdot (1-2x-2y)$

$3)\ \ y=3x-2\ \ ,\ \ \ A(\, 0\, ;-2\, )\ \ ,\ \ B(\, \frac{2}{3}\, ;\, 0\, )$

 Смотри рисунок .

$4)\ \ \left\{\begin{array}{l}y-2x=2\\2x-4y=10\end{array}\right\ \oplus \ \left\{\begin{array}{l}2x=y-2\\-3y=12\end{array}\right\ \ \left\{\begin{array}{ccc}2x=-6\\y=-4\end{array}\right\ \ \left\{\begin{array}{l}x=-3\\y=-4\end{array}\right$

$5)\ \ a)\ \ \dfrac{5x+1}{2}-2x=3\ \ ,\ \ \ \ 5x+1-4x=6\ \ ,\ \ \ \ x=5\\\\b)\ \ 4\, (1-5x)=9-3\, (6x-5)\ \ ,\ \ \ \ 4-20x=9-18x+15\ \ ,\\\\2x=-20\ \ ,\ \ \ \ x=-10$