\(=a\left(x+y\right)-7\left(x+y\right)=\left(a-7\right)\left(x+y\right)\)

7x-7y+ax-ay=(7x-7y)+(ax-ay)=7(x-y)+a(x-y)=(x-y)(7+a)

7x-7y+ax-ay

=(7x-7y)+(ax-ay)

=7(x-y)+a(x-y)

=(x-y)(7+a)

b) ax^2 + ay - bx^2 - by

= x^2(a-b) - y(a-b)

= (x^2 - y) (a-b)

c)

x²+5x+6

=x²+5x-+25/4-25/4+6

=(x+5/2)²-1/4

=(x+5/2-1/2)(x+5/2+1/2)

=(x-2)(x+3)

a)

a²x+a²y-7x-7y

=a²(x+y)-7(x+y)

=(a²-7)(x+y)

a) \(A=x^2-8x-y^2-8y\)

\(A=\left(x^2-y^2\right)-\left(8x+8y\right)\)

\(A=-8\left(x-y\right)\left(x+y\right)\)

b) \(B=x^2-6x+9-4y^2\)

\(B=\left(x-3\right)^2-\left(2y\right)^2\)

\(B=\left(x-3-2y\right)\left(x-3+2y\right)\)

c) \(C=7x-7y-ax+ay\)

\(C=7\left(x-y\right)-a\left(x-y\right)\)

\(C=\left(x-y\right)\left(7-a\right)\)

\(A=\left(x^2-8x+16\right)-\left(y^2+8y+16\right)=\left(x-4\right)^2-\left(y+4\right)^2=\left(x-4+y+4\right)\left(x-4-y-4\right)=\left(x+y\right)\left(x-y-8\right)\)

\(B=\left(x^2-6x+9\right)-4y^2=\left(x-3+2y\right)\left(x-3-2y\right)\)

\(C=7\left(x-y\right)-a\left(x-y\right)=\left(7-a\right)\left(x-y\right)\)

1 \(=\left(4x^2+4x+1\right)-\left(3y\right)^2\)

     \(=\left(2x+1\right)^2-\left(3y\right)^2\)

      \(=\left(2x+1-3y\right)\left(2x+1+3y\right)\)

2,\(=\left(x^2+2xy+y^2\right)-\left(z^2-2zt+t^2\right)\)

     \(=\left(x+y\right)^2-\left(z-t\right)^2\)

     \(=\left(x+y+z-t\right)\left(x+y-z+t\right)\)

3,\(=9x\left(x-y\right)-7\left(x-y\right)\)

    \(=\left(x-y\right)\left(9x-7\right)\)

4\(=3\left(x-y\right)+a\left(x-y\right)\)

   \(=\left(x-y\right)\left(3+a\right)\)

a) sửa đề nha bn: xy + xz - 5z - 5y

\(xy+xz-5z-5y\)

\(=x\left(y+z\right)-5\left(z+y\right)\)

\(=\left(x-5\right)\left(y+z\right)\)

b) \(x+y-x^2-xy\)

\(=\left(x+y\right)-x\left(x+y\right)\)

\(=\left(1-x\right)\left(x+y\right)\)

c) \(x^2-xy-7x+7y\)

\(=x\left(x-y\right)-7\left(x-y\right)\)

\(=\left(x-7\right)\left(x-y\right)\)

d) \(ax^2+cx^2-ay+ay^2-cy+cy^2\)

\(=ax^2+cx^2-ay-cy+ay^2+cy^2\)

\(=x^2\left(a+c\right)-y\left(a+c\right)+y^2\left(a+c\right)\)

\(=\left(a+c\right)\left(x^2-y+y^2\right)\)

\(\dfrac{15x}{7y^5}.\dfrac{2y^2}{x^6}=\dfrac{30xy^2}{7x^6y^5}=\dfrac{30}{7x^5y^3}\\ \rightarrow a=5;b=3\)

a) x⁴ - x³ - x² + 1

=(x⁴ - x³) -(x² + 1²)

=x³(x-1)-(x+1)(x-1)

=(x-1)

nhầm 

(x-1)(x³ + x+ 1)

\(b,=\left(x+y\right)-x\left(x+y\right)=\left(1-x\right)\left(x+y\right)\\ c,=x\left(x-y\right)-7\left(x-y\right)=\left(x-7\right)\left(x-y\right)\\ d,=x^2\left(a+c\right)-y\left(a+c\right)+y^2\left(a+c\right)\\ =\left(x^2-y+y^2\right)\left(a+c\right)\)

Câu a sai đề, không phân tích được

a: \(xy+xz-5x-5y=\left(x+y\right)\left(z-5\right)\)

b: \(x+y-x^2-xy=\left(x+y\right)\left(1-x\right)\)

c: \(x^2-xy-7x+7y=\left(x-y\right)\left(x-7\right)\)