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 ▸

Find the gradient of the curve with the equation y = x^3+7x^2+1 at x=2


Simplify the following C4 question into it's simplest form: (x^4-4x^3+9x^2-17x+12)/(x^3-4x^2+4x)


The lines y = 3x² - x + 5/2 intersects the line y = x/2 +7 at two points. Give their coordinates. Show your working


Find the stationary points of the curve y=x^4-8x^2+3 and determine their nature.