Question

   Phân tích đa thức thành nhân tử :

a) 9(a-b)²-4(x-y)²  

b) (a²+9)²-36a²

c) (x+y)²-2(x+y)+1

Answer 1

\(9\left(a-b\right)^2-4\left(x-y\right)^2\)

\(=\left[3\left(a-b\right)\right]^2-\left[2\left(x-y\right)\right]^2\)

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

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

Answer 2

\(\left(a^2+9\right)^2-36a^2\)

\(=\left(a^2+9\right)^2-\left(6a\right)^2\)

\(=\left(a^2-6a+9\right)\left(a^2+6a+9\right)\)

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

Answer 3

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

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

Answer 4

9( a - b )^2 - 4(x - y)^2

= [3(a - b)]^2 - [2(x - y)]^2

= (3a - 

Answer 5

a) \(=[3\left(a-b\right)]^2-[2\left(x-y\right)]^2\)

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

b)\(=\left(a^2+3^2\right)^2-\left(6a\right)^2\)

\(=\left(a^2-2.a.3+3^2\right)\left(a^2+2.a.3+3^2\right)\)

\(=\left(a-3\right)^2.\left(a+3\right)^2\)

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

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

nhớ tích nha