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: Kết quả quy đồng mẫu thức của hai phân thức: 5/3x+15 ;3/x^-25

Toán Lớp 8: Kết quả quy đồng mẫu thức của hai phân thức: 5/3x+15 ;3/x^-25

Comments ( 2 )

  1. 5/(3x+15)
    = 5/[3.(x+5)]
    = [5.(x-5)]/[3(x+5)(x-5)]
    3/(x^2-25)
    = 3/[(x-5)(x+5)]
    = 9/[3(x-5)(x+5)]

  2. Giải đáp:
     $\text{*Ta cs:}$
    $\text{3x+15= 3.(x+5)}$
    $\text{x²-25= (x-5).(x+5)}$
    $\text{→ MTC= 3.(x-5).(x+5)}$
    $\text{*Ta lại cs:}$
    $\text{ 3.(x-5).(x+5):3.(x+5)=x-5}$
    $\text{3.(x-5).(x+5):(x-5).(x+5)=3}$
    $\text{*Quy đồng:}$
    $\dfrac{5}{3x+15}= \dfrac{5.(x-5)}{3.(x-5).(x+5)}= \dfrac{5x-25}{3.(x-5).(x+5)}$
    $\dfrac{3}{x²-25}= \dfrac{3.3}{(x-5).(x+5).3}= \dfrac{9}{3.(x-5).(x+5)}$
    $Vậy$ $\dfrac{5}{3x+15}= \dfrac{5x-25}{3.(x-5).(x+5)}$ $;$ $\dfrac{3}{x²-25}= \dfrac{9}{3.(x-5).(x+5}$
    $\text{#HAPPY}$
     

Leave a reply

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