Given that r={-3}{4} and s={1}{-3}, find r-2s.

Correct Answer is : (−510)\; \; {-5}{10}(10−5)

Correct Answer is : (−510)\; \; {-5}{10}(10−5)

Test Index

BECE Mathematics 2012 Paper

Question : 27

Total: 40

Given that

r=\binom{-3}{4}

s=\binom{1}{-3}

r-2s

Solution:

Multiplying a vector by a number

c\binom{a}{b}=c\times\binom{a}{b}=\begin{pmatrix} a & \times & c \\ b & x & c \end{pmatrix}

Addition of vectors

\binom{a}{b}+\binom{c}{d}=\binom{a+c}{b+d}

Subtraction of vectors

\;\binom{a}{b}-\binom{c}{d}=\binom{a-c}{b-d}

\; r=\binom{-3}{4} \;\text{ and }\; s=\binom{1}{-3}

\; r-2s=\binom{-3}{4}-2\binom{1}{-3}

\; r-2s=\binom{-3}{4}-\binom{1\times 2}{-3\times 2}

\; r-2s=\binom{-3}{4}-\binom{2}{-6}

\; r-2s=\begin{pmatrix} -3 & -2 \\ 4- & -6 \end{pmatrix}

\; -=+

\; r-2s=\binom{-5}{4+6}

\; r-2s=\binom{-5}{10}

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