BECE Mathematics 2015 Paper

Concept:A mapping rule expresses each input $x$ in terms of its output $y$.Find the operation that changes every $x$ into the matching $y$.Explanation:Look at the pairs: $1 \to 1$, $2 \to 4$, $3 \to 9$, $4 \to 16$, $5 \to 25$.Each $y$-value is the square of its $x$-value.So the rule should be $y = x^2$.Check this with the first two values:When $x=1$, $y = 1^2 = 1$.When $x=2$, $y = 2^2 = 4$.Now test the other options using $x=1$:Option A: $y = x+2 = 1+2 = 3$, which is not $1$.Option B: $y = 2x = 2(1) = 2$, which is not $1$.Option D: $y = 2x+2 = 2(1)+2 = 4$, which is not $1$.Only option C matches all the values in the mapping.Answer:C. $y \rightarrow x^2$