1, 3x-15=2x(x-5) 2, x^2-x=0 3, x^2-2x=0 4, x^2-3x=0 5, (x+1)(x+2)=(2-x)(x+2) can gap ah camon!!!

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1. Giải thích các bước giải:

   1) 3x-15=2x(x-5)

   ⇔ 3x-15=2x²-10x

   ⇔ -2x²+3x+10x-15=0

   ⇔ -2x²+13x-15=0

   ⇔ 2x²-13x+15=0

   ⇔ 2x²-10x-3x+15=0

   ⇔ (2x²-10x)-(3x-15)=0

   ⇔ 2x(x-5)-3(x-5)=0

   ⇔ (2x-3)(x-5)=0

   ⇔ \(\left[ \begin{array}{l}2x-3=0\\x-5=0\end{array} \right.\) 

   ⇔ \(\left[ \begin{array}{l}x=$\frac{3}{2}$ \\x=5\end{array} \right.\)

   Vậy…………….

   2) x²-x=0

   ⇔ x(x-1)=0

   ⇔ \(\left[ \begin{array}{l}x=0\\x-1=0\end{array} \right.\)

   ⇔  \(\left[ \begin{array}{l}x=0\\x=1\end{array} \right.\) 

   Vậy…..

   3) x²-2x=0

   ⇔ x(x-2)=0

   ⇔ \(\left[ \begin{array}{l}x=0\\x-2=0\end{array} \right.\)

   ⇔ \(\left[ \begin{array}{l}x=0\\x=2\end{array} \right.\)

   Vậy….

   4) x²-3x=0

   ⇔ x(x-3)=0

   ⇔ \(\left[ \begin{array}{l}x=0\\x-3=0\end{array} \right.\)

   ⇔ \(\left[ \begin{array}{l}x=0\\x=3\end{array} \right.\)

   Vậy……

   5) (x+1)(x+2)=(2-x)(x+2)

   ⇔ (x+1)(x+2)-(2-x)(x+2)=0

   ⇔ (x+2)[(x+1)-(2-x)]=0

   ⇔ (x+2)(x+1-2+x)=0

   ⇔ (x+2)(2x-1)=0

   ⇔ \(\left[ \begin{array}{l}x+2=0\\2x-1=0\end{array} \right.\) 

   ⇔ \(\left[ \begin{array}{l}x=-2\\x= $\frac{1}{2}$ \end{array} \right.\)

   Vậy…………

   Trả lời

2. 1, 3x-15= 2x( x-5)

   ⇔ 3x -15 = 2x² -10x

   ⇔ 3x -2x² +10x -15 = 0

   ⇔ -2x² +13x -15 = 0

   ⇔ -2x² +10x +3x -15 = 0

   ⇔ -2x(x -5) +3(x-5) = 0

   ⇔ (x-5).(-2x +3) = 0

   TH1: x-5 = 0 ⇔ x = 5

   TH2: -2x+3 = 0 ⇔ x= 3/2

   Vậy S= {5; 3/2}

   2, x(x-1)= 0

   ⇔\(\left[ \begin{array}{l}x=0\\x-1=0\end{array} \right.\) 

   ⇔\(\left[ \begin{array}{l}x=0\\x=1\end{array} \right.\) 

   Vậy S ={0; 1}

   3, x(x-2)=0

   Bạn làm tương tự như câu 2, nha . Mk cho kết quả thôi nhé!

   Vậy S ={0; 2}

   4, x(x-3)=0

   Câu này cx thế nhé!

   Vậy S ={0; 3}

   5, x²+2x+x+2=2x+4-x²-2x

     ⇔ x²+2x+x+2-2x-4+x²+2x=0

     ⇔2x²+3x – 2  =0

   ⇔2x²-x+4x -2 =0

   ⇔ x.(2x-1)+2(2x-1)=0

   ⇔\(\left[ \begin{array}{l}2x-1=0\\x+2=0\end{array} \right.\)

   ⇔\(\left[ \begin{array}{l}x=1/2\\x=-2\end{array} \right.\) 

   Vậy S = {1/2; -2}

   Trả lời