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, 5x^2 + 36x + 7 = 0 2, 2x^2 – 2x -4 =0 3, x^2 – 9x + 8 =0 4, x^2 -7x +6 =0 5, x^2 +10x -11 =0 6. 3x^2 – 8x + 5 =0 7, -2x^2

Tháng Một 11, 2023 Toán học 2 Comments 0 views

Toán Lớp 8: 1, 5x^2 + 36x + 7 = 0
2, 2x^2 – 2x -4 =0
3, x^2 – 9x + 8 =0
4, x^2 -7x +6 =0
5, x^2 +10x -11 =0
6. 3x^2 – 8x + 5 =0
7, -2x^2 + 3x -1 =0
8, 5x^2 -7x + 2=0
9 , -x^2 + 4x + 5 =0
10, x^2 – 8x + 16 =0

Comments ( 2 )

  1. minhtuyethue
    minhtuyethue
    11 Tháng Một, 2023 at 7:56 sáng
    Reply
    1)5x²+36x+7=0
    ⇔5x²+35x+x+7=0
    ⇔5x(x+7)+(x+7)=0
    ⇔(x+7)(5x+1)=0
    ⇔$\left[\begin{matrix} x+7=0\\ 5x+1=0\end{matrix}\right.$
    ⇔$\left[\begin{matrix} x=-7\\ x=-\dfrac{1}{5}\end{matrix}\right.$
    Vậy S={-7;-1/5}
    2)2x²-2x-4=0
    ⇔2x²+2x-4x-4=0
    ⇔2x(x+1)-4(x+1)=0
    ⇔(x+1)(2x-4)=0
    ⇔$\left[\begin{matrix} x+1=0\\ 2x-4=0\end{matrix}\right.$
    ⇔$\left[\begin{matrix} x=-1\\ x=2\end{matrix}\right.$
    Vậy S={-1;2}
    3)x²-9x+8=0
    ⇔x²-8x-x+8=0
    ⇔x(x-8)-(x-8)=0
    ⇔(x-8)(x-1)=0
    ⇔$\left[\begin{matrix} x-8=0\\ x-1=0\end{matrix}\right.$
    ⇔$\left[\begin{matrix} x=8\\ x=1\end{matrix}\right.$
    Vậy S={8;1}
    4)x²-7x+6=0
    ⇔x²-6x-x+6=0
    ⇔x(x-6)-(x-6)=0
    ⇔(x-6)(x-1)=0
    ⇔$\left[\begin{matrix} x-6=0\\ x-1=0\end{matrix}\right.$
    ⇔$\left[\begin{matrix} x=6\\ x=1\end{matrix}\right.$
    Vậy S={6;1}
    5)x²+10x-11=0
    ⇔x²+11x-x-11=0
    ⇔x(x+11)-(x+11)=0
    ⇔(x+11)(x-1)=0
    ⇔$\left[\begin{matrix} x+11=0\\ x-1=0\end{matrix}\right.$
    ⇔$\left[\begin{matrix} x=-11\\ x=1\end{matrix}\right.$
    Vậy S={-11;1}
    6)3x²-8x+5=0
    ⇔3x²-3x-5x+5=0
    ⇔3x(x-1)-5(x-1)=0
    ⇔(x-1)(3x-5)=0
    ⇔$\left[\begin{matrix} x-1=0\\ 3x-5=0\end{matrix}\right.$
    ⇔$\left[\begin{matrix} x=1\\ x=\dfrac{5}{3}\end{matrix}\right.$
    Vậy S={1;5/3}
    7)-2x²+3x-1=0
    ⇔-2x²+2x+x-1=0
    ⇔-2x(x-1)+(x-1)=0
    ⇔(x-1)(-2x+1)=0
    ⇔$\left[\begin{matrix} x-1=0\\ -2x+1=0\end{matrix}\right.$
    ⇔$\left[\begin{matrix} x=1\\ x=\dfrac{1}{2}\end{matrix}\right.$
    Vậy S={1;1/2}
    8)5x²-7x+2=0
    ⇔5x²-5x-2x+2=0
    ⇔5x(x-1)-2(x-1)=0
    ⇔(x-1)(5x-2)=0
    ⇔$\left[\begin{matrix} x-1=0\\ 5x-2=0\end{matrix}\right.$
    ⇔$\left[\begin{matrix} x=1\\ x=\dfrac{2}{5}\end{matrix}\right.$
    Vậy S={1;2/5}
    9)-x²+4x+5=0
    ⇔-x²-x+5x+5=0
    ⇔-x(x+1)+5(x+1)=0
    ⇔(x+1)(-x+5)=0
    ⇔$\left[\begin{matrix} x+1=0\\ -x+5=0\end{matrix}\right.$
    ⇔$\left[\begin{matrix} x=-1\\ x=5\end{matrix}\right.$
    Vậy S={-1;5}
    10)x²-8x+16=0
    ⇔x²-2.x.4+4²=0
    ⇔(x-4)²=0
    ⇔x-4=0
    ⇔x=4
    Vậy S={4}

  2. tuyetnhungthu
    tuyetnhungthu
    11 Tháng Một, 2023 at 7:55 sáng
    Reply
    khôg hiểu ở đâu thì hỏi nhá????

    toan-lop-8-1-5-2-36-7-0-2-2-2-2-4-0-3-2-9-8-0-4-2-7-6-0-5-2-10-11-0-6-3-2-8-5-0-7-2-2

Leave a reply

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

Kiều Nguyệt

About Kiều Nguyệt