(2x - 7) + 17 = 6
=> 2x - 7 = 6 - 17
=> 2x - 7 = -11
=> 2x = -11 + 7
=> 2x = -4
=> x = -4 : 2
=> x = -2
+) 12 -2(3 - 3x)= -2
=> 2(3 - 3x) = 12 + 2
=> 2(3 - 3x) = 14
=> 3 - 3x = 14 : 2
=> 3 - 3x = 7
=> 3x = 3 - 7
=> 3x = -4
=> x = -4/3
\(\left(x+1\right)\left(x-3\right)=0\)
=> \(\orbr{\begin{cases}x+1=0\\x-3=0\end{cases}}\)
=> \(\orbr{\begin{cases}x=-1\\x=3\end{cases}}\)
Vậy...
\(\left(2x-7\right)+17=6\)
\(\left(2x-7\right)=6-17\)
\(2x-7=-11\)
\(2x=-11+7\)
\(2x=-4\)
\(x=-4:2\)
\(\Rightarrow x=-2\)
\(V\text{ậy x = -2}\)
\(12-2.\left(3-3x\right)=-2\)
\(10.\left(3-3x\right)=-2\)
\(\left(3-3x\right)=10:-2\)
\(3-3x=-5\)
\(3x=3-\left(-5\right)\)
\(3x=8\)
\(x=8:3\)
\(x=2,666666667\)
\(a,\left(2x-7\right)+17=6\)
\(\Leftrightarrow2x+10=6\)
\(\Leftrightarrow2x=-4\)
\(\Leftrightarrow x=-2\)
\(b,12-2\left(3-3x\right)=-2\)
\(\Leftrightarrow12+2=2\left(3-3x\right)\)
\(\Leftrightarrow14=6-6x\)
\(\Leftrightarrow14-6=-6x\)
\(\Leftrightarrow-6x=8\)
\(\Leftrightarrow x=-\frac{8}{6}=-\frac{4}{3}\)
\(-14+3\left(-x+5\right)=-20\)
\(\Leftrightarrow-14+3\left(-x+5\right)=-20\)
\(\Leftrightarrow-14+\left(-3x\right)+15=-20\)
\(\Leftrightarrow1+20=3x\)
\(\Leftrightarrow x=7\)
\(c,-90:5\left(-3-2x\right)=6\)
\(\Leftrightarrow-18\left(-3-2x\right)=6\)
\(\Leftrightarrow54+36x=6\)
\(\Leftrightarrow36x=-48\)
\(\Leftrightarrow x=-\frac{48}{36}\)
\(\left(x+1\right)\left(x+3\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x+1=0\\x+3=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=-1\\x=-3\end{cases}}\)
\(\left(2x-2\right)\left(x+3\right)=0\)
\(\Leftrightarrow2\left(x-1\right)\left(x+3\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x-1=0\\x+3=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=1\\x=-3\end{cases}}\)
\(\left(5-x\right)\left(6-2x\right)=0\)
\(\Leftrightarrow\left(5-x\right)2\left(3-x\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}5-x=0\\3-x=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=5\\x=3\end{cases}}\)
\(3\left(x+1\right)+5=x+8\)
\(\Leftrightarrow3x+3+5=x+8\)
\(\Leftrightarrow2x=0\)
\(\Leftrightarrow x=0\)
