a) \(15+2\left|x\right|=-3\\ \\ < =>2\left|x\right|=15-\left(-3\right)\\ < =>2\left|x\right|=18\\ =>\left|x\right|=\frac{18}{2}=9\\ =>x=9hoặcx=-9\)
b) \(\left|x-2\right|=7\\ < =>x-2=7hoặcx-2=-7\\ =>x=9hoặcx=-5\)
c) \(100-4.x^2=224\\ < =>4.x^2=100-224=-124\\ < =>x^2=-\frac{124}{4}=-31\\ Mà:x^2\ge0\\ =>xkhôngcógiátrịnàothoảmãn\)
d)\(2x-\frac{9}{240}=\frac{39}{80}\\ < =>2x-\frac{3}{80}=\frac{39}{80}\\ =>2x=\frac{39}{80}+\frac{3}{80}=\frac{21}{40}\\ =>x=\frac{\frac{21}{40}}{2}=\frac{21}{80}\)
\(15+2\left|x\right|=-3\)
\(\Rightarrow2\left|x\right|=15+3\)
\(\Rightarrow2\left|x\right|=18\)
\(\Rightarrow\left|x\right|=\frac{18}{2}\)
\(\Rightarrow\left|x\right|=9\)
\(\Rightarrow\left[\begin{matrix}x=9\\x=-9\end{matrix}\right.\)
Vậy, x = 9 hoặc x = -9.
\(\left|x-2\right|=7\)
\(\Rightarrow\left|x\right|=9\)
\(\Rightarrow\left[\begin{matrix}x=9\\x=-9\end{matrix}\right.\)
