Foil & Reverse-Foil, Algebra for GMAT | Quantitative for GMAT PDF Download

ALGEBRA

FOIL & REVERSE-FOIL

FOIL – First, Outer, Inner, Last is a math concept that involves Quadratics. You will be asked to FOIL and Reverse FOIL on the GMAT, so these skills are a must.

FOIL Example: 

(x + 3)(x + 3)

x² + 6x + 9 = 0

Reverse FOIL Example:

x² + 6x + 9 = 0 

(x + 3)(x + 3)

First 

Outer 

Inner 

Last 

The 3 Classic Quadratics are worth knowing since most test takers will see one or more of them on the GMAT. They’re sometimes “hidden” behind other math concepts though (large numbers or the square root symbol), so pay careful attention to how questions are formatted (if you see squared terms, then you might be dealing with a classic quadratic) Here are the 3 Classic quadratics. Can you FOIL them out? 

(x + y)(x + y) = 0 

(x – y)(x – y) = 0 

(x + y)(x - y) = 0 

SYMBOLISM 

Symbolism questions involve a “made up” math symbol. The question will tell you what the symbol means and then will ask you to perform a calculation using the symbol. These questions tend to be rather easy, so pay attention to what the symbol means and do the math correctly.

Example: 
aΩb = ab + a²
2Ω3 = 2.3 + 2²
= 6+4
= 10