Test Index

WAEC Further Mathematics 2021 Paper

Question : 11

Total: 38

^2

- 12x + k, a perfect square?

Solution:

Concept:

A quadratic expression is a perfect square when its discriminant equals zero, i.e.

b^2 - 4ac = 0

Explanation:

Given expression:

4x^2 - 12x + k

Compare with

ax^2 + bx + c

So,

a = 4

b = -12

, and

c = k

For a perfect square, use the condition

b^2 = 4ac

Substitute the values:

(-12)^2 = 4 \times 4 \times k

This gives

144 = 16k

Divide both sides by 16:

k = \frac{144}{16}= 9

Answer:

k = 9

Thus, the correct option is D.

Go to Question:

Prev Question

Next Question