a, \(\left|x+2,9\right|-1,4=0,3\)
\(\left|x+2,9\right|=0,3+1,4\)
\(\left|x+2,9\right|=1,7\)
TH 1 :
=> x + 2,9 = 1,7
x = 1,7 - 2,9
x = -1,2
TH 2:
=> x + 2,9 = -1,7
x = -1,7 + 2,9
x = 4,6
b, \(x^2-\frac{5}{14}x=0\)
\(x^2.1-\frac{5}{14}x=0\)
\(x\left(1-\frac{5}{14}\right)x=0\)
\(x^2.\frac{9}{14}=0\)
\(x^2=0:\frac{9}{14}\)
\(x^2=0\)
=> x = 0
a) \(\left|x+2,9\right|-1,4=0,3\)
⇒ \(\left|x+2,9\right|=0,3+1,4\)
⇒ \(\left|x+2,9\right|=1,7\)
⇒ \(\left[{}\begin{matrix}x+2,9=1,7\\x+2,9=-1,7\end{matrix}\right.\) ⇒ \(\left[{}\begin{matrix}x=1,7-2,9\\x=\left(-1,7\right)-2,9\end{matrix}\right.\) ⇒ \(\left[{}\begin{matrix}x=-1,2\\x=-4,6\end{matrix}\right.\)
Vậy \(x\in\left\{-1,2;-4,6\right\}.\)
Chúc bạn học tốt!
