How to find a Quadratic Equation When Its Roots Are Given?
In this lesson I will discuss how to find the quadratic equation when its roots are given.
To find the quadratic equation I will multiply the “x – first root” to “x – second root”.
What that means?
Let’s do it by taking an example. Find the quadratic equation whose roots are “-1” and “3”.
Solution: I will find the product of {x – (-1)} and (x – 3) and mark it equal to zero as shown below;
{x – (-1)} (x – 3) = 0
(x + 1) (x – 3) = 0
Then I use FOIL to expand at the Left Hand Side
x² – 3x – x – 3 = 0
x² – 4x – 3 = 0
Above is my quadratic equation whose roots are “-1” and “3”.
Exercise: Find the quadratic equation with roots 2 and -4.
Following are the links to my previous posts on quadratic equations and functions;
https://steemit.com/steemiteducation/@mathworksheets/sum-and-product-of-roots-of-a-quadratic-equation
https://steemit.com/steemiteducation/@mathworksheets/solving-quadratic-equations-using-the-formula
https://steemit.com/steemiteducation/@mathworksheets/the-quadratic-formula-let-s-drive-it
https://steemit.com/steemiteducation/@mathworksheets/completing-the-square-of-a-quadratic-equation-3
https://steemit.com/steemiteducation/@mathworksheets/graphing-the-simplest-quadratic-function
https://steemit.com/steemiteducation/@mathworksheets/quadratic-functions-an-introduction