Conversion of an equation

Math Central

Quandaries & Queries

Question from Marie, a student:

How to you convert the equation of a line from x-intercept form
(y=(x-x1)(x-x2)) to general form (y=ax^2+bx+c) if it involves square
roots?

For example:
Convert this equation to general form: y=(x+the square root of 5)^2

Thanks for the help!

Hi Marie,

I am sure that you know that

\[\left( a + b \right)^2 = a^2 + 2ab + b^{2}.\]

Try this expansion with

\[\left( x + \sqrt{5} \right)^{2}.\]

Write back if you need more assistance,
Penny

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