BECE Mathematics 2018 Paper

Concept:Anticlockwise rotation by $90^{\circ}$ about the origin transforms any point $(x, y)$ to $(-y, x)$.Explanation:For an anticlockwise rotation of $90^{\circ}$ about the origin, the rule is:$$\binom{x}{y} \rightarrow \binom{-y}{x}$$This means the coordinates are switched and the new $x$-coordinate is the negative of the original $y$-coordinate.Given point $Q(-4, 5)$ can be written as $\binom{-4}{5}$.Applying the rule:$$\binom{-4}{5} \rightarrow \binom{-5}{-4}$$So the image is $Q'(-5, -4)$.Matching with the options, this corresponds to option B.Answer:$Q'(-5, -4)$ (Option B)