Given that a={2}{3} and b={-1}{4}, evaluate ≤ft(2 a - 1/4 b).

Correct Answer is : (174)≤ft( {}¹7/4} )(417)5

Correct Answer is : (174)≤ft( {}¹7/4} )(417)5

Test Index

WAEC Further Mathematics 2017 Paper

Question : 30

Total: 40

Given that

a=\binom{2}{3}

b=\binom{-1}{4}

\left(2 a - \frac{1}{4} b\right)

Solution:

Concept:

Scalar multiplication and subtraction of column vectors.

Explanation:

First, compute

2a

2a = 2\binom{2}{3} = \binom{4}{6}

Next, compute

\frac{1}{4}b

\frac{1}{4}b = \frac{1}{4}\binom{-1}{4} = \binom{-\frac14}{1}

Now subtract component-wise.

First component:

4 - \left(-\frac14\right) = \frac{17}{4}

Second component:

6 - 1 = 5

Hence,

2a - \frac{1}{4}b = \binom{\frac{17}{4}}{5}

Answer:

\binom{\frac{17}{4}}{5}

, which is Option B.

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