Quant Ch 2 - Linear & Quadratic Equations

Question 1

Substitution method

Answer 1

Solving a system of equations with multiple variables by isolating 1 variable from 1 equation and subbing it into the other equation

Question 2

Combination method

Answer 2

Solving a system of equations with multiple variables by adding or subtracting 1 equation from another to eliminate 1 variable and solve for the other

Question 3

FOIL

Answer 3

First, Outside. Inside Last

Used to take a quad equation from (x+p)(x+q) –> ax² + bx + c

Question 4

3 quadratic identities

Answer 4

(x+y)² = (x+y)(x+y) = x² + y² + 2xy

(x-y)² = (x-y)(x-y) = x² + y² - 2xy

(x+y)(x-y) = x² - y²

Question 5

Difference of squares

Answer 5

To spot a difference in squares, look for the square of a value minus the square of another value. If you notice a difference of squares in an equation, try to simplify it in this way.

(x+y)(x-y) = x² - y²

Question 6

Method to express -1

Answer 6

When x ≠ y:
(x-y) / (y-x) = -1

Question 7

Constant terms (c) and coefficients in quadratic equations

Answer 7

If you are given a solution for an equation with a constant (c) and coefficient (k), solve for either number then plug that number back into the equation

Question 8

“C” Trap

Answer 8

When 2 statements appear obviously sufficient together, but only 1 of the equations is sufficient