Question

Помогите c алгеброй пж очень надо

Answer 1

$tt 1.~~ a),(2a-1)^2=(2a)^2-2cdot2acdot1+1^2=4a^2-4a+1\ b)~(x+3y)^2=x^2+2cdot xcdot 3y+(3y)^2=x^2+6xy+9y^2\ c)~ (0.2x-y)(0.2x+y)=(0.2x)^2-y^2=0.04x^2-y^2$

$tt 2.~ a)~ (c-2)(c+3)-(c-1)^2=c^2-2c+3c-6-(c^2-2c+1)=\ =c^2+c-6-c^2+2c-1=3c-7\ \ b)~ 3(a+c)^2-6ac=3(a^2+2ac+c^2)-6ac=3a^2+6ac+3c^2-6ac=\ =3a^2+3c^2=3(a^2+c^2)\ \ c)~ (p-3)(p^2+3p+9)-p^3=p^3-3^3-p^3=p^3-27-p^3=-27$

$tt 3.~ (12a^3-3a^2b):3a=3a^2(4a-b):3a=a(4a-b)$

Если а = -2 и b = 10, то $tt a(4a-b)=(-2)cdot(4cdot(-2)-10)=36$