How do you use the quadratic formula?

The equation for the quadratic formula is x = (-b +/- √(b^2 - 4ac))/2a for when the equation ax^2 + bx + c is equal to 0. When you have the equation ax^2 + bx + c, where a, b and c are given numbers, you can sub the numbers into the quadratic formula to find x.For example, you are given 2x^2 + 6x + 4 = 0 and asked to find x. Here you can see that a=2 , b=6 and c=4. You can then sub these into the quadratic formula to give x = (-6 +/- √(6^2 - 4(2)(4)))/2(2) and put this into your calculator to find that x = -2 or -1.

Answered by Isla B. Maths tutor

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