B = \binom{4}{ - 18} Given that -2a = b, write a as a column vector.​

Question

`b = \binom{4}{ - 18}`
Given that -2a = b, write a as a column vector.​

Answer 1

`a=\left[\begin{array}{ccc}-2 \\9 \end{array}\right]}`

Explanation:

Given:

`b=\left[\begin{array}{ccc}4\\-18\end{array}\right]\\\\-2a=b`

Find:

`a=\left[\begin{array}{ccc}??\\??\end{array}\right]`

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`-2a=b\\\\\Longrightarrow a=-(1)/(2)b\\ \\\Longrightarrow a=-(1)/(2)\left[\begin{array}{ccc}4\\-18\end{array}\right] \\\\\Longrightarrow a=\left[\begin{array}{ccc}4(-(1)/(2)) \\-18(-(1)/(2)) \end{array}\right]\\\\\therefore \boxed{\boxed{a=\left[\begin{array}{ccc}-2 \\9 \end{array}\right]}}`