x^2 - 9x + 20 = 0 factorises as (x - 4)(x - 5) = 0. If you solved the same equation by the quadratic formula instead, what happens?

Question

Accepted Answer

The formula gives x = 9 ± 1/2, i.e. 5 and 4 — exactly the same roots. D = 81 - 80 = 1, √D = 1. x = 9 ± 1/2 = 5 or 4. Both methods must agree; the formula simply always works, while factorisation only helps when the factors are easy to spot.

$x^{2} - 9 x + 20 = 0$ factorises as $(x - 4) (x - 5) = 0$ .
If you solved the same equation by the quadratic formula instead, what happens?

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 10 The Quadratic Formula practice

x2−9x+20=0 factorises as (x−4)(x−5)=0.If you solved the same equation by the quadratic formula instead, what happens?

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 10 The Quadratic Formula practice

$x^{2} - 9 x + 20 = 0$ factorises as $(x - 4) (x - 5) = 0$ .
If you solved the same equation by the quadratic formula instead, what happens?