Advertisements (Quảng cáo)
Tìm x, biết:
a) \(\left| x \right| = {4 \over 5}\)
b) \(\left| x \right| = – 9,37\)
c) \(\left| x \right| = 0\)
d) \(\left| {2x} \right| = 7{1 \over 2}\)
e) \(\left| {x – 3} \right| = 4\)
Advertisements (Quảng cáo)
\(a)\left| x \right| = {4 \over 5}\) thì \(x = {4 \over 5}\) hoặc \(x = {{ – 4} \over 5}\)
b)\(\left| x \right| = – 9,37\) thì \(x \in \phi \)
c) \(\left| x \right| = 0\) thì x=0
d) \(\eqalign{ & \left| {2x} \right| = 7{1 \over 2} \cr & \left| {2x} \right| = {{15} \over 2} \cr & 2x = {{15} \over 2}hoặc2x = – {{15} \over 2} \cr & x = {{15} \over 4}hoặcx = – {{15} \over 4} \cr & x = 3{3 \over 4}hoặcx = – 3{3 \over 4} \cr} \)