Toán Lớp 8: 1)14x^2-21xy^2+28x^2y^2
2)x^2+4x-y^2+4
3)x^2+5x-6
4)a^4+16
5)x^2-y^2-2x+2y
6)2x+2y-x^2-xy
7)3a^2-6ab+3b^2-12c^2
8)x^2-25+y^2+2xy
9)a^2+2ab+b^2-ac-bc
10)x^2-2x-4y^2-4y
Leave a reply
Register Now
Login
Lost Password
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Toán Lớp 8: 1)14x^2-21xy^2+28x^2y^2
2)x^2+4x-y^2+4
3)x^2+5x-6
4)a^4+16
5)x^2-y^2-2x+2y
6)2x+2y-x^2-xy
7)3a^2-6ab+3b^2-12c^2
8)x^2-25+y^2+2xy
9)a^2+2ab+b^2-ac-bc
10)x^2-2x-4y^2-4y
Comments ( 2 )
=(a^2+4)^2-(2$\sqrt[]{2}$ a)^2
=(a^2+4+2$\sqrt[]{2}$ a)(a^2+4-2$\sqrt[]{2}$a)
=7xy(2x-3y+4xy)
= x^2 + 4x + 4- y^2
= (x+2)^2 — y^2
= (x+2-y)(x+2+y)
= x^2 – x + 6x – 6
= x(x-1) + 6(x-1)
= (x-1)(x+6)
= 2 ( x + y) – x ( x + y)
= ( 2 – x ) ( x + y)
x^2-2x-4y^2-4y
= x^2 – 4y^2 – 2x – 4y
= x- 2y) ( x + 2y) – 2( x – 2y)
= ( x – 2y) ( x + 2y – 2)
= (x-y)(X+y) – 2(x-y)
= (x-y)(x+y-2
= x^4 + 2^4
= x^4 + 4x^2 + 16 -4x^2 ( cộng và trừ thêm 4x^2 )
= (x^2 + 2).(x^2 + 2) – (2x)^2
= (x^2 + 2)^2 -(2x)^2
= (x^2 +2 -2x).(x^2 +2 +2x)