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: tìm x, biết a) 5x + 1/5x – 2 + 36 – 1/3x = 12 b)7x ( x – 2 ) – 5 . ( x – 1 ) = 7$x^{2}$ + 3 c) 2 . ( 5x – 8 ) – 3 . ( 4x – 5 ) = 4 . (

Toán Lớp 8: tìm x, biết
a) 5x + 1/5x – 2 + 36 – 1/3x = 12
b)7x ( x – 2 ) – 5 . ( x – 1 ) = 7$x^{2}$ + 3
c) 2 . ( 5x – 8 ) – 3 . ( 4x – 5 ) = 4 . ( 3x – 4 ) + 11
giúp mik với ạ, hứa vote 5 sao

Comments ( 1 )

  1. #Sad
    a)
    5x+(1)/(5)x-2+36-(1)/(3)x = 12
    ⇔ (5x+(1)/(5)x-(1)/(3)x)+(-2+36) = 12
    ⇔ (73)/(15)x+34 = 12
    ⇔ (73)/(15)x = -22
    ⇔ x = -(330)/(73)
    \text{Vậy S=} {-(330)/(73)}
    b)
    7x(x-2)-5(x-1) = 7x^2+3
    ⇔ 7x^2-14x-5x+5-7x^2-3 = 0
    ⇔ (7x^2-7x^2)+(-14-5x)+(5-3) = 0
    ⇔ -19x+2 = 0
    ⇔ -19x = -2
    ⇔ x = 2/(19)
    \text{Vậy S=} {2/(19)}
    c)
    2(5x-8)-3(4x-5) = 4(3x-4)+11
    ⇔ 10x-16-12x+15 = 12x-16+11
    ⇔ -2x-1 = 12x-5
    ⇔ -2x-12x = 1-5
    ⇔ -14x = -4
    ⇔ x = 4/(14)
    \text{Vậy S=} {4/(14)}
     

Leave a reply

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