BECE Mathematics 2015 Paper

Concept:Substitute the given value of the variable into the expression and simplify using the correct order of operations.Explanation:The expression is: $(3m)^2 - 3m^2$Substitute $m = 2$ into the expression.$(3m)^2 - 3m^2 = (3 \cdot 2)^2 - 3 \cdot 2^2$First simplify the term inside the parentheses: $3 \cdot 2 = 6$.So the expression becomes: $6^2 - 3 \cdot 2^2$Now evaluate each power: $6^2 = 36$ and $2^2 = 4$.This gives: $36 - 3 \cdot 4$Multiply: $3 \cdot 4 = 12$.So the expression becomes: $36 - 12$Finally, subtract: $36 - 12 = 24$.Answer:The value of the expression is $24$.Therefore, the correct option is D. 24.