BECE Mathematics 2022 Paper

Concept:Substitute the given values into the formula, taking care with the signs of negative numbers.Formula used:$x = \dfrac{b^2 - 4ac}{2a}$Given:$a = 2$, $b = -4$, $c = -2$Solution:$b^2 = (-4)^2 = 16$$4ac = 4 \times 2 \times (-2) = -16$$b^2 - 4ac = 16 - (-16) = 16 + 16 = 32$$2a = 2 \times 2 = 4$$x = \dfrac{32}{4} = 8$Key point: $(-4)^2 = +16$, and subtracting $-16$ means adding $16$. Writing $16 - 16 = 0$ gives the trap answer $0$.Answer:Option B ($8$)