BECE Mathematics 2025 Paper

Concept:Difference of two squares: $(a - b)(a + b) = a^2 - b^2$. The middle terms cancel.Solution:Here $a = 8s$ and $b = 7$.Expanding fully: $(8s - 7)(8s + 7) = 64s^2 + 56s - 56s - 49$The middle terms cancel: $56s - 56s = 0$$= (8s)^2 - 7^2 = 64s^2 - 49$Key point: $(8s)^2 = 64s^2$, not $16s^2$; square both the 8 and the $s$. The last term is $-7 \times 7 = -49$, negative.Answer:Option B ($64s^2 - 49$)