If you want to bring your “A Game” on the Quant section you need to be very comfortable with Algebra.
There is one mathematical discipline that dominates the Quant section of the GMAT: Algebra. The majority of the math questions that you will see on test day involve algebra.
Many questions involve pure algebra, such as expressions and equations involving variables, roots, and exponents. Another large group of questions is word problems, most of which are best addressed using algebraic equations. Geometry is another significant subject on the GMAT; and geometry is simply a delivery mechanism for algebra. Even things like ratios can often best be addressed by using equations with “x” as the multiplier.