What is the quadratic formula and how do I use it?

The quadratic formula is a way of solving quadratic equations of the form: ax2+bx+c=0. By plugging in the values a,b and c into it, the solutions for x can be obtained:x = [-b +/- sqrt(b2-4ac)]/2a For example, solving 2x2+3x-5=0:a = 2, b = 3, c = -5 so inputting these values into the formula above:x = [-3 +/- sqrt(32-4(2*-5)]/(2*2)x = 1 or x = -5/2These can be checked by inserting them into the original equation, or using a graphical method looking at the x-intercept coordinates.

PM

Related Maths GCSE answers

All answers ▸

Differentiate the equation 3x^4+6x^2-7x+2


How to calculate conditional probabilities? E.g, say we roll a fair standard six sided die, what is the probability we rolled a 2, given that the roll is even?


How does Pythagoras Theorem work?


Explain how to solve simulatentous equations.