What is the larger root of x^2 - 1x - 2 = 0?
Answer and explanation
Correct answer: A. 2
- Step 1: Find two numbers with product -2 and sum 1: they are 2 and -1. Step 2. The equation factorises as (x - 2)(x + 1) = 0. Step 3. The roots are x = 2 and x = -1, so the larger is 2. Answer: 2. Why not the others: -1: That is the smaller root. -2: The sign is wrong: if (x - r) is a factor, the root is +r. 1: That is the smaller root with its sign reversed.
Practise more Quadratic equations.
Free questions with an explanation for every one, and full timed Kenya KCSE mock tests.