SOLUTION: This is actually about "unfoiling". Is there a quick and easy way to figure out the binomials when unfoiling. As an example: 2x^2 - 9x + 4. How do I know how to choose the righ

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: This is actually about "unfoiling". Is there a quick and easy way to figure out the binomials when unfoiling. As an example: 2x^2 - 9x + 4. How do I know how to choose the righ      Log On


   

Question 40108: This is actually about "unfoiling". Is there a quick and easy way to figure out the binomials when unfoiling. As an example:
2x^2 - 9x + 4. How do I know how to choose the right numbers to factor this into two binomials? Is there a different rule for positive and/or negative numbers.
Thanks very much.
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
IF THE FIRST & THIRD NUMBERS ARE + & THE MISSLE NUMBER IS - THEN THE FIRST OR THE THIRD FACTORS MUST BOTH BE NEGATIVE.
THUS IN THIS CASE WE HAVE (2X-1)(X-4) OR (-2X+1)(-X+4) IN EITHER CASE WE HAVE
X=1/2 & X=4