-28-7.|-3x+15|=-70
|18-2|-x+5||=12
12-2.{-x+3}=-38
-20+3.{2x+1}=-101
giúp mình với
-28-7.|-3x+15|=-70 |18-2|-x+5||=12 12-2.{-x+3}=-38 -20+3.{2x+1}=-101 giúp mình với
By Parker
By Parker
-28-7.|-3x+15|=-70
|18-2|-x+5||=12
12-2.{-x+3}=-38
-20+3.{2x+1}=-101
giúp mình với
Đáp án:
d) x=-14
Giải thích các bước giải:
\(\begin{array}{l}
a) – 28 – 7\left| { – 3x + 15} \right| = – 70\\
\to 7\left| { – 3x + 15} \right| = 42\\
\to \left| { – 3x + 15} \right| = 6\\
\to \left[ \begin{array}{l}
– 3x + 15 = 6\\
– 3x + 15 = – 6
\end{array} \right.\\
\to \left[ \begin{array}{l}
x = 3\\
x = – 7
\end{array} \right.\\
b)\left| {18 – 2\left| { – x + 5} \right|} \right| = 12\\
\to \left[ \begin{array}{l}
18 – 2\left| { – x + 5} \right| = 12\\
18 – 2\left| { – x + 5} \right| = – 12
\end{array} \right.\\
\to \left[ \begin{array}{l}
2\left| { – x + 5} \right| = 6\\
2\left| { – x + 5} \right| = 30
\end{array} \right.\\
\to \left[ \begin{array}{l}
\left| { – x + 5} \right| = 3\\
\left| { – x + 5} \right| = 15
\end{array} \right.\\
\to \left[ \begin{array}{l}
– x + 5 = 3\\
– x + 5 = – 3\\
– x + 5 = 15\\
– x + 5 = – 15
\end{array} \right. \to \left[ \begin{array}{l}
x = 2\\
x = 8\\
x = – 10\\
x = 20
\end{array} \right.\\
c)12 – 2\left( { – x + 3} \right) = – 38\\
\to 2\left( { – x + 3} \right) = 50\\
\to 3 – x = 25\\
\to x = – 22\\
d) – 20 + 3\left( {2x + 1} \right) = – 101\\
\to 3\left( {2x + 1} \right) = – 81\\
\to 2x + 1 = – 27\\
\to x = – 14
\end{array}\)