How do you know how many roots a quadratic equation has?

To work out the number of roots a qudratic ax2​+bx+c=0 you need to compute the discriminant (b2​-4ac).

If the discrimant is less than 0, then the quadratic has no real roots.

If the discriminant is equal to zero then the quadratic has equal roosts.

If the discriminant is more than zero then it has 2 distinct roots.

LC

Related Maths A Level answers

All answers ▸

What is integration by parts?


y = 4x^3 - 5/x^2 Find dy/dx


A cannon at ground level is firing at a fort 200m away with 20m high walls. It aims at an angle 30 degrees above the horizontal and fires cannonballs at 50m/s. Assuming no air resistance, will the cannonballs fall short, hit the walls or enter the fort?


Why does 'x' need to be in radians to differentiate 'sin x'?