a) 7x = -14
=> x = -2
b) 6x - (-5) = 17
=> 6x = (-5) + 17
=> 6x = 12
=> x = 12
c ) ( x + 2 ) . ( x - 9 ) = 0
=> x + 2 = 0 hoặc x - 9 = 0
=> x = -2 ; x = 9
a, x = -2
b, 6x = 12
x = 2
c, \(\orbr{\begin{cases}x=-2\\x=9\end{cases}}\)
\(a,7x=-14\)
<=>\(x=-2\)
\(b,6x-\left(-5\right)=17\)
<=>\(6x+5=17\)
<=>\(6x=12\)
<=>\(x=2\)
\(c,\left(x+2\right)\left(x-9\right)=0\)
<=>\(\orbr{\begin{cases}x+2=0\\x-9=0\end{cases}}\)
<=>\(\orbr{\begin{cases}x=-2\\x=9\end{cases}}\)
Mình nhầm câu b). câu b) x= 2 nhé
a) 7x = -14
x = -14 : 7
x = -2
b) 6x -(-5) =17
6x = 17-5
6x = 12
x =2
c) (x+2).(x-9) =0
\(\Leftrightarrow\hept{\begin{cases}x+2=0\\x-9=0\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x=-2\\x=9\end{cases}}\)
a) 7.x = -14
<=> x = (-14 ) : 7
<=> x = -2
Vậy x = -2
b) 6.x - ( -5 ) = 17
<=> 6.x + 5 = 17
<=> 6.x = 17 -5
<=> x =12 : 6
<=> x = 2
Vậy x = 2
c, \(\left(x+2\right).\left(x-9\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x+2=0\Rightarrow x=-2\\x-9=0\Rightarrow x=9\end{cases}}\)
Vậy x = -2 hoặc x = 9
a)7x=-14
x =-14:7
x =-7
b)6x-(-5)=17
6x+5 =17
6x =17-5
6x =12
x =12:6
x =2
c)(x+2).(x-9)=0
suy ra x+2=0 hoặc x-9=0
+)x+2=0 thì x=-2
+)x-9=0 thì x=9
Vậy x bằng -2 hoặc 9
\(a,7x=-14\Leftrightarrow x=-2\)
\(b,6x-\left(-5\right)=17\)
\(6x+5=17\)
\(6x=12\Leftrightarrow x=2\)
\(c,\left(x+2\right)\left(x-9\right)=0\)
\(Th1:x+2=0\Leftrightarrow x=-2\)
\(x-9=0\Leftrightarrow x=9\)
\(a,7x=-14\)
\(\Rightarrow x=-2\)
Chúc bạn học tốt~~
\(a,7x=-14\)
\(=>x=\frac{-14}{7}=-2\)
\(b,6x-\left(-5\right)=17\)
\(=>6x=17-5=12\)
\(=x=\frac{12}{6}=2\)
\(c=\left(x+2\right).\left(x-9\right)=0\)
\(=>\orbr{\begin{cases}x+2=0\\x-9=0\end{cases}=>\orbr{\begin{cases}x=-2\\x=9\end{cases}}}\)
a) 7x = -14
x = -14 : 7
x = -2
Vậy x = -2
b) 6x - (-5) = 17
6x + 5= 17
6x = 17 - 5
6x = 12
x = 12 : 6
x = 2
Vậy x = 2
c) (x + 2 ) . (x - 9) = 0
\(\Rightarrow\orbr{\begin{cases}x+2=0\\x-9=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=0-2=-2\\x=0+9=9\end{cases}}\)
vậy.................................
