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 9: √4x-20 +3 √x-5/9 – 1/3 √9x-45 bằng 4 √3x-2 bé hơn 5 giúp em với ạ

Toán Lớp 9: √4x-20 +3 √x-5/9 – 1/3 √9x-45 bằng 4
√3x-2 bé hơn 5
giúp em với ạ

Comments ( 1 )

  1. a) \sqrt{4x-20}+3\sqrt{(x-5)/(9)}-1/3\sqrt{9x-45}=4 (x>=5)
    ⇔\sqrt{4(x-5)}+(3\sqrt{x-5})/(3)-1/3\sqrt{9(x-5)}=4
    ⇔2\sqrt{x-5}+\sqrt{x-5}-\sqrt{x-5}=4
    ⇔2\sqrt{x-5}=4
    ⇔\sqrt{x-5}=2
    ⇔x-5=4
    ⇔x=9 ™
    Vậy S={9}
    b) \sqrt{3x-2}<5 (x>=2/3)
    ⇔3x-2<25
    ⇔3x<27
    ⇔x<9
    Vậy S={x|2/3<=x<9}
     

Leave a reply

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