1) 3a - 3b + a^2 - ab

= 3(a - b) + a(a - b)

= (a - b)(a + 3)

2) = 3xy(x^2 + y^2)/(x^2 + y^2) = 3xy

\(a,15a^2b^3+5a^3b^2=5a^2b^2\left(3b+a\right)\\ b,x^2-2x+1-y^2=\left(x-1\right)^2-y^2=\left(x-y-1\right)\left(x+y-1\right)\)

a) 15a²b³+5a³b²=5a²b²(3b+a)
b) x²-2x+x-y²=( x²-y²⁾-(2x+x)
                     =(x-y)(x+y)-x(2-1)
                      =(x-y)(x+y)-x3

Bạn xem lại đề bài nhé.

(b-a-5)*(b-a)

a²+b²-5b-2ab+5a
= (b²-2ab+a²)-5(b-a)
= (b-a)²-5(b-a)
= (b-a)(b-a-5)

a, 16a² - 4b³ = 4.(4a² - b³)

b, 3x³ + 45 = 3.(x³ + 15)

a) \(16a^2-4b^3\)

\(=4\left(4a^2-b^2\right)\)

b) \(3x^3+45\)

\(=3\left(x^3+15\right)\)

\(1,\\ 1,=15\left(x+y\right)\\ 2,=4\left(2x-3y\right)\\ 3,=x\left(y-1\right)\\ 4,=2x\left(2x-3\right)\\ 2,\\ 1,=\left(x+y\right)\left(2-5a\right)\\ 2,=\left(x-5\right)\left(a^2-3\right)\\ 3,=\left(a-b\right)\left(4x+6xy\right)=2x\left(2+3y\right)\left(a-b\right)\\ 4,=\left(x-1\right)\left(3x+5\right)\\ 3,\\ A=13\left(87+12+1\right)=13\cdot100=1300\\ B=\left(x-3\right)\left(2x+y\right)=\left(13-3\right)\left(26+4\right)=10\cdot30=300\\ 4,\\ 1,\Rightarrow\left(x-5\right)\left(x-2\right)=0\Rightarrow\left[{}\begin{matrix}x=2\\x=5\end{matrix}\right.\\ 2,\Rightarrow\left(x-7\right)\left(x+2\right)=0\Rightarrow\left[{}\begin{matrix}x=7\\x=-2\end{matrix}\right.\\ 3,\Rightarrow\left(3x-1\right)\left(x-4\right)=0\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{3}\\x=4\end{matrix}\right.\\ 4,\Rightarrow\left(2x+3\right)\left(2x-1\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=-\dfrac{3}{2}\\x=\dfrac{1}{2}\end{matrix}\right.\)