Question 142394

Lets just use a+bi and then you can use any value of a and b that you like.

Using the FOIL (First, Outer, Inner, Last) crutch, we'll multiply a+bi by a-bi

(a+bi)(a-bi)=a^2-abi+abi-b^2i^2 but i^2=-1, so we have:

a^2+b^2-------------------------------------Ans

a-bi is called the conjugate of a+bi and the conjugate is commonly used to eliminate the radical in the denominator of an equation or expression.

Hope this helps---ptaylor