Rút gọn các biểu thức sau: c) ( 2/ x+2- 2/ 1-x). x^2-4/ 4x^2-1 ;
Giải thích
c, 2x+2−21−x.x2−44x2−1=2(1−x)−2(x+2)(x+2)(1−x).(x+2)(x−2)(2x−1)(2x+1)
=(−4x−2)(x−2)(1−x)(2x−1)(2x+1)=−2(2x+1)(x−2)(1−x)(2x−1)(2x+1)=−2x+4(1−x)(2x−1)=2x−4x−12x−1
c, 2x+2−21−x.x2−44x2−1=2(1−x)−2(x+2)(x+2)(1−x).(x+2)(x−2)(2x−1)(2x+1)
=(−4x−2)(x−2)(1−x)(2x−1)(2x+1)=−2(2x+1)(x−2)(1−x)(2x−1)(2x+1)=−2x+4(1−x)(2x−1)=2x−4x−12x−1