Problem

$7: 43$
11 of 12
(?) $O A B$ form a triangle.
\[
\begin{array}{l}
\overrightarrow{O A}=a+2 b \\
\overrightarrow{O B}=3 a+7 b
\end{array}
\]
Express the vector $\overrightarrow{A B}$ in terms of $a$ and/or $b$.

Give your answer in its simplest form.
The diagram is not drawn to scale.
AA
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Answer

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Answer

\(\boxed{\overrightarrow{AB} = 2a + 5b}\)

Steps

Step 1 :Given: \(\overrightarrow{OA} = a + 2b\) and \(\overrightarrow{OB} = 3a + 7b\)

Step 2 :To find \(\overrightarrow{AB}\), subtract \(\overrightarrow{OA}\) from \(\overrightarrow{OB}\): \(\overrightarrow{AB} = \overrightarrow{OB} - \overrightarrow{OA}\)

Step 3 :\(\overrightarrow{AB} = (3a + 7b) - (a + 2b)\)

Step 4 :\(\overrightarrow{AB} = 2a + 5b\)

Step 5 :\(\boxed{\overrightarrow{AB} = 2a + 5b}\)

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