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: 1/ thực hiện các phép tính sau 2) 4x + 1 2x-3 ===- + ==– = 7 7 4) x^2 4x + 4 =-

Toán Lớp 8: 1/ thực hiện các phép tính sau
2) 4x + 1 2x-3
———- + ——– =
7 7

4) x^2 4x + 4
——– + ——– =
3x+6 3x + 6

6) 2x – 5 -3x + 40 x + 3
———— + ——— + ———- =
x -7 7 – x x – 7

Comments ( 2 )

  1. 2) $\dfrac{4x + 1}{7}$ + $\dfrac{2x – 3}{7}$
    = $\dfrac{4x + 1 + 2x – 3}{7}$
    = $\dfrac{6x – 2}{7}$
    $\\$
    4) $\dfrac{x^2}{3x + 6}$ + $\dfrac{4x + 4}{3x + 6}$    điều kiện: x $\neq$ 0; x $\geq$ – 2
    = $\dfrac{x^2 + 4x + 4}{3x + 6}$
    = $\dfrac{(x + 2)^2}{3(x + 2)}$
    = $\dfrac{x + 2}{3}$
    $\\$
    6) $\dfrac{2x – 5}{x – 7}$ + $\dfrac{- 3x + 40}{7 – x}$ + $\dfrac{x + 3}{x – 7}$   
    điều kiện: x $\neq$ 0; x $\geq$ 7
    = $\dfrac{2x – 5}{x – 7}$ – $\dfrac{3x + 40}{x – 7}$ + $\dfrac{x + 3}{x – 7}$
    = $\dfrac{2x – 5 – (3x + 40) + x + 3}{x – 7}$
    = $\dfrac{2x – 5 – 3x – 40 + x + 3}{x – 7}$
    = $\dfrac{2x – 3x + x – 5 – 40 + 3}{x – 7}$
    = $\dfrac{- 42}{x – 7}$
     #Ling

  2. 4x + 1     2x-3           4x+1+2x-3            6x-2
    —— + ——-= ————–   =———–
       7               7                    7                          7
     x^2           4x+4               x^2 +4x+4         (x+2)^2         x+2
    —— + ———- =      ———— =————= ——–
    3x+6           3x+6                 3x+6              3(x+2)               3
    2x-5              -3x+40          x+3          2x-5+3x+40+x+3          6x+38
    ——-   +     ———    + —— =——————– =————-
    x-7                       7-x             x-7                x-7                                 x-7
    Chúc bạn học tốt

Leave a reply

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

About Khanh