How to factor 2x^2 — 1

Question

Hi, how do i factor 2x²—1 ? 

Answer 1

You can look at this as the difference of two squares

[(√2)x]² = 2x²

 

Recall the formula   (a²-b²) = (a-b)(a+b)

 

2x² -1 = (x√2)² - (1)²

 

= (x√2 - 1)(x√2 + 1)