Tìm số nguyên x, biết
a) (3x – 6) + 3 = 32
b) (3x – 6) – 3 = 32
c) (3x – 6) . 3 = 32
d) (3x – 6) : 3 = 32
e) (3x -24).73 = 2.74
f) |x| = |-7|
g) |x+1| = 2
h) |x+1| = 3 và x+1< 0
i) x +|-2| = 0
j) 4.(3x – 4) – 2 = 18
Tìm số nguyên x, biết a) (3x – 6) + 3 = 32 b) (3x – 6) – 3 = 32 c) (3x – 6) . 3 = 32 d) (3x – 6) : 3 = 32 e) (3x -24).73 = 2.74 f) |x| = |-7| g) |x+1|
By Hailey
Đáp án:
j) x=3
Giải thích các bước giải:
\(\begin{array}{l}
a)3x – 6 = 29\\
\to 3x = 35\\
\to x = \dfrac{{35}}{3}\\
b)3x – 6 = 35\\
\to 3x = 41\\
\to x = \dfrac{{41}}{3}\\
c)3x – 6 = \dfrac{{32}}{3}\\
\to 3x = \dfrac{{50}}{3}\\
\to x = \dfrac{{50}}{9}\\
d)3x – 6 = 96\\
\to 3x = 102\\
\to x = 34\\
e)3x – 24 = \dfrac{{148}}{{73}}\\
\to 3x = \dfrac{{1900}}{{73}}\\
\to x = \dfrac{{1900}}{{219}}\\
f)\left| x \right| = \left| { – 7} \right|\\
\to \left| x \right| = 7\\
\to \left[ \begin{array}{l}
x = 7\\
x = – 7
\end{array} \right.\\
g)\left| {x + 1} \right| = 2\\
\to \left[ \begin{array}{l}
x + 1 = 2\\
x + 1 = – 2
\end{array} \right.\\
\to \left[ \begin{array}{l}
x = 1\\
x = – 3
\end{array} \right.\\
h)\left| {x + 1} \right| = 3\\
\to x + 1 = – 3\left( {do:x + 1 < 0} \right)\\
\to x = – 4\\
i)x = – \left| { – 2} \right|\\
\to x = – 2\\
j)3x – 4 = 5\\
\to 3x = 9\\
\to x = 3
\end{array}\)