BECE Mathematics 2019 Paper

Concept:A mapping rule must give the correct $y$-value for every given $x$-value.Substitute the known pairs into each option to identify the correct rule.Explanation:From the mapping, when $x=1$, the corresponding value is $y=3$.Test Option A: $y=2x+2$.For $x=1$: $y=2(1)+2=4 \neq 3$. So A is incorrect.Test Option B: $y=-2x+2$.For $x=1$: $y=-2(1)+2=0 \neq 3$. So B is incorrect.Test Option C: $y=4x$.For $x=1$: $y=4(1)=4 \neq 3$. So C is incorrect.Test Option D: $y=-2x+5$.For $x=1$: $y=-2(1)+5=3$. This matches.Verify with another value: for $x=2$, $y=-2(2)+5=1$.For $x=3$, $y=-2(3)+5=-1$.All given pairs satisfy this rule.Answer:The correct rule of the mapping is $y=-2x+5$, which is Option D.