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.

222-9+11+12:2*14+14 = ? ( )

Toán Lớp 8: B= ($\frac{x+1}{1-x}$ -$\frac{1-x}{1+x}$-$\frac{4x^{2}}{x^{2}-1}$): $\frac{4x^2-4}{x^2-2x+1}$ Rút gọn

Toán Lớp 8: B= ($\frac{x+1}{1-x}$ -$\frac{1-x}{1+x}$-$\frac{4x^{2}}{x^{2}-1}$): $\frac{4x^2-4}{x^2-2x+1}$ Rút gọn

Comments ( 2 )

  1. Giải đáp:
     
    Lời giải và giải thích chi tiết:
     B=([x+1]/[1-x]-[1-x]/[1+x]-[4x^2]/[x^2 -1] ):[4x^2 -4]/[x^2 -2x+1]
    =([-x-1]/[x-1] +[x-1]/[x+1] -[4x^2]/[(x-1)(x+1)]):[4(x-1)(x+1)]/[(x-1)^2]
    =[(-x-1)(x+1)+(x-1)(x-1)-4x^2 ]/[(x-1)(x+1)].[x-1]/[4(x+1)]
    =[-x^2 -2x-1+x^2 -2x+1-4x^2 ]/[x+1]. 1/[4(x+1)]
    =[-4x^2 -4x]/[x+1]. 1/[4(x+1)]
    =[-4x(x+1)]/[4(x+1)(x+1)]
    =[-x]/[x+1]
    (Bài tham khảo)

  2. B=((x+1)/(1-x)-(1-x)/(1+x)-(4x^2)/(x^2-1)):(5x^2-4)/(x^2-2x+1)(x\ne+-1)
    ->B=(-(x+1)/(x-1)-(1-x)/(x+1)-(4x^2)/((x-1)(x+1))):(4(x-1)(x+1))/((x-1)^2)
    ->B=(-(x+2)^2+(x-1)^2-4x^2)/((x-1)(x+1)):(4(x-1))/(x-1)
    ->B=(-4x-4x^2)/((x-1)(x+1)) . (x-1)/(4(x-1))
    ->B=(-x)/(x+1)
    Với x\ne+-1 thì B=(-x)/(x+1)
    #Mon
    $@Tr$ 
     

Leave a reply

222-9+11+12:2*14+14 = ? ( )

About Hoa