a) \(2x-13=7\)
\(\Leftrightarrow2x=7+13=20\)
\(\Leftrightarrow x=\frac{20}{2}=10\)
b) \(23-x=31-\left(-9\right)\)
\(\Leftrightarrow23-x=40\)
\(\Leftrightarrow x=23-40=-17\)
c) \(\left|x+13\right|-4=16\)
\(\Leftrightarrow\left|x+13\right|=16+4=20\)
\(\Leftrightarrow\left[\begin{matrix}x+13=20\Rightarrow x=7\\x+13=-20\Rightarrow x=-33\end{matrix}\right.\)
d) Vì 45 \(⋮x\) mà x > 15
\(\Rightarrow\) x = 45
a, 2x = 7 + 13 =20 => x = 20 : 2 =10
b, 23 - x = 31 + 9 = 40 => x = 23 - 40 = -17
c, x = 7 ; x = -33
d, x = 22,5
a, \(2x-13=7\)
\(2x=7+13\)
\(2x=20\)
\(x=\frac{20}{2}\)
\(x=10\)
b, \(23-x=31-\left(-9\right)\)
\(23-x=40\)
\(x=23-40\)
\(x=-17\)
c, \(\left|x+13\right|-4=16\)
\(\left|x+13\right|=16+4\)
\(\left|x+13\right|=20\)
\(\Rightarrow\left[\begin{matrix}x+13=20\\x+13=-20\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=7\\x=-33\end{matrix}\right.\)
d, \(45⋮x;x>15\)
Vì \(45⋮x\) nên x là Ư(45)
Mà \(Ư\left(45\right)=\left\{1;3;5;9;15;45\right\}\)
Vì x > 15 nên x = 45.
a. 2x-13=7
=>2x=30=>x=15
b. 23-x=31-(-9)
=>23-x=40=>x=-17
c. /x+13/-4=16
=>/x+13/=20
\(\Rightarrow\left[\begin{matrix}x+13=20\\x+13=-20\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=7\\x=-33\end{matrix}\right.\)
