Question

因式分解1/4x^2-y^2 (2x+1)^2-(x-2)^2 (m+n)^2-n^2 169(a-b)^2-196(a+b)^2 (2x+y)^2-(x+2y)^2

(a+b+c)^2-(a+b-c)^2 1.4^2×16-2.2×4快快快快7点前给我加10

Answer 1

1/4x^2-y^2
=（1/2x+y)(1/2x-y)
(2x+1)^2-(x-2)^2
=(2x+1-x+2)(2x+1+x-2)
=(x+3)(3x-1)
(m+n)^2-n^2
=(m+n+n)(m+n-n)
=(m+2n)m
169(a-b)^2-196(a+b)^2
=(13a-13b+14a+14b)(13a-13b-14a-14b)
=-(27a+b)(a+27b)
(2x+y)^2-(x+2y)^2
=(2x+y+x+2y)(2x+y-x-2y)
=(3x+3y)(x-y)
=3(x+y)(x-y)
(a+b+c)^2-(a+b-c)^2
=(a+b+c+a+b-c)(a+b+c-a-b+c)
=(2a+2b)2c
=4c(a+b)