Câu trong ảnh làm như nào các bạn ơi... $a,~A=(2xy+1)^2-(2x+y)^2.$ $b,~A=x^2-2xy+y^2-4.$,$a,~A=9.(x-y)^2-4.(x+y)^2.$ $b,~A=x^2-2xy+y^2-z^2.$,$a,~A=(3x-2y)^2-(2x-3y)^2.$ $b,~A=25-x^2+4xy-4x^2.$,$a,~A=(4x^2-4x+1)-(x+1)^2.$ $b,~A=x^2+x^2-2xy-4z^2.$,$a,~A=x^2+x-12.$ $b,~A=3+7x+2x^2.$ $c,~A=4x^2-5xy+y^2.$,$a,~A=x^2-4x-5.$ $b,~A=4+3x^2-8x.$ $c,~A=x^2-4xy+3y^2.$,$a,~A=x^2-2x-3.$ $b,~A=3x^2+2-7x.$ $c,~A=9x^2+6xy-8x^2.$

Question

Accepted Answer

{"userId":5168711,"userName":"Hữu Hiền Minh Nguyễn"}

1.

a) A = (2xy + 1)² - (2x + y)²

= [(2xy + 1) - (2x + y)] × [(2xy + 1) + (2x + y)]

= (2xy - 2x - y + 1) × (2xy + 2x + y + 1)

b) A = x² - 2xy + y² - 4

= (x - y)² - 2²

= (x - y - 2)(x - y + 2)

2.

a) A = 9(x - y)² - 4(x + y)²

= [3(x - y)]² - [2(x + y)]²

= [3(x - y) - 2(x + y)] × [3(x - y) + 2(x + y)]

= (3x - 3y - 2x - 2y)(3x - 3y + 2x + 2y)

= (x - 5y)(5x - y)

b) A = x² - 2xy + y² - z²

= (x - y)² - z²

= (x - y - z)(x - y + z)

3.

a) A = (3x - 2y)² - (2x - 3y)²

= [(3x - 2y) - (2x - 3y)] × [(3x - 2y) + (2x - 3y)]

= (x + y)(5x - 5y)

= 5(x + y)(x - y)

b) A = 25 - x² + 4xy - 4y²

= (5)² - (x - 2y)²

= (5 - (x - 2y))(5 + (x - 2y))

= (5 - x + 2y)(5 + x - 2y)

4.

a) A = (4x² - 4x + 1) - (x + 1)²

= (4x² - 4x + 1) - (x² + 2x + 1)

= 4x² - 4x + 1 - x² - 2x - 1

= 3x² - 6x

= 3x(x - 2)

b) A = x² + y² - 2xy - 4z²

= (x - y)² - (2z)²

= (x - y - 2z)(x - y + 2z)

5.

a) A = x² + x - 12

= x² + 4x - 3x - 12

= x(x + 4) - 3(x + 4)

= (x + 4)(x - 3)

b) A = 3 + 7x + 2x²

= 2x² + 7x + 3

= (2x + 1)(x + 3)

c) A = 4x² - 5xy + y²

= (4x² - 4xy) - (xy - y²)

= 4x(x - y) - y(x - y)

= (x - y)(4x - y)

6.

a) A = x² - 4x - 5

= x² - 5x + x - 5

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

= (x - 5)(x + 1)

b) A = 4 + 3x² - 8x

= 3x² - 8x + 4

= 3x² - 6x - 2x + 4

= 3x(x - 2) - 2(x - 2)

= (x - 2)(3x - 2)

c) A = x² - 4xy + 3y²

= (x² - xy) - (3xy - 3y²)

= x(x - y) - 3y(x - y)

= (x - y)(x - 3y)

7.

a) A = x² - 2x - 3

= x² - 3x + x - 3

= x(x - 3) + 1(x - 3)

= (x - 3)(x + 1)

b) A = 3x² + 2 - 7x

= 3x² - 7x + 2

= 3x² - x - 6x + 2

= x(3x - 1) - 2(3x - 1)

= (3x - 1)(x - 2)

c) A = 9x² + 6xy - 8y²

= (9x² + 12xy) - (6xy + 8y²)

= 3x(3x + 4y) - 2y(3x + 4y)

= (3x + 4y)(3x - 2y)