a) |x| = 3
⇒\(\left[ \begin{array}{l}x=3\\x=-3\end{array} \right.\)
b) |x| - 8 = -3
⇒ |x| = -3 + 8
⇒ |x| = 5
⇒\(\left[ \begin{array}{l}x=5\\x=-5\end{array} \right.\)
c) |x| = 0
⇒ x = 0
d) |x| + 4 = 0
⇒ |x| = 0 - 4
⇒ |x| = -4
⇒ x ∈ Ф ( Vì không giá trị tuyệt đối nào bằng số nguyên âm)
⇒\(\left[ \begin{array}{l}x=4\\x=-4\end{array} \right.\)
e) |x+1| = 2
⇒\(\left[ \begin{array}{l}x+1=2\\x+1 = -2\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x=2 - 1\\x=-2 - 1\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x=1\\x=-3\end{array} \right.\)
g) |2x+1| - 3 = 0
⇒ |2x+1| = 0 + 3
⇒ |2x+1| = 3
⇒\(\left[ \begin{array}{l}2x +1=3\\2x+1=-3\end{array} \right.\)
⇒\(\left[ \begin{array}{l}2x=3-1\\2x=-3 - 1\end{array} \right.\)
⇒\(\left[ \begin{array}{l}2x=2\\2x=-4\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x=2:2\\x=-4 : 2\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x=1\\x=-2\end{array} \right.\)
h) 3.|2x-3} + 1 = 10
⇒ 3.|2x-3| = 10 - 1
⇒ 3.|2x-3| = 9
⇒ |2x-3| = 9 : 3
⇒ |2x-3| = 3
⇒\(\left[ \begin{array}{l}2x-3=3\\2x-3=-3\end{array} \right.\)
⇒\(\left[ \begin{array}{l}2x=3+3\\2x=-3 + 3\end{array} \right.\)
⇒\(\left[ \begin{array}{l}2x=6\\2x=0\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x=6 : 2\\x=0 : 2\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x=3\\x=0\end{array} \right.\)
Chúc bạn học tốt!
