PCH1: Basic Arithmetic & Algebra

Question 1

Sum by difference

Answer 1

(a+b)(a-b) = a^2 - b^2

Question 2

Difference of two squares

Answer 2

x^2 - y^2 = (x + y) (x - y)

Question 3

sum of two cubes

Answer 3

x^3 + y^3 = (x+y) (x^2 - xy + y^2)

Question 4

difference of two cubes

Answer 4

x^3 - y^3 = (x - y) (x^2 + xy + y^2)

Question 5

sum of a square

Answer 5

(a + b)^2 = a^2 + 2ab + b^2

Question 6

difference of a square

Answer 6

(a - b)^2 = a^2 - 2ab + b^2

Question 7

quadratic formula

Answer 7

x = - b +/- √ b^2 - 4ac
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2a