MATHS EN LIGNE - STI_1G1. MathsGéo : La géométrie en 4ème et 3ème de collège. Mathadoc. Completing the Square: Solving Quadratic Equations. Completing the Square: Solving Quadratic Equations (page 1 of 2) Some quadratics are fairly simple to solve because they are of the form "something-with-x squared equals some number", and then you take the square root of both sides. An example would be: (x – 4)2 = 5 x – 4 = ± sqrt(5) x = 4 ± sqrt(5) x = 4 – sqrt(5) and x = 4 + sqrt(5) Unfortunately, most quadratics don't come neatly squared like this. For your average everyday quadratic, you first have to use the technique of "completing the square" to rearrange the quadratic into the neat "(squared part) equals (a number)" format demonstrated above. For example: Find the x-intercepts of y = 4x2 – 2x – 5.
First off, remember that finding the x-intercepts means setting y equal to zero and solving for the x-values, so this question is really asking you to "Solve 4x2 – 2x – 5 = 0". The answer can also be written in rounded form as You will need rounded form for "real life" answers to word problems, and for graphing.