Find the roots of the quadratic function by completing the square: x^2 + 4x - 1 = 0

x = - 2 ±

Step-by-step explanation:

Given

x² + 4x - 1 = 0 ( add 1 to both sides )

x² + 4x = 1

To complete the square

add (half the coefficient of the x- term )² to both sides

x² + 2(2)x + 2² = 1 + 2² ← complete the square on the left side

(x + 2)² = 5 ← take the square root of both sides

x + 2 = ± ← subtract 2 from both sides

x = - 2 ±

roots are x = - 2 - or x = - 2 +

because linear equations are a lot simpler than quadratics equations, and linear equations formula is a lot easier to memorize. that's why i think they're harder.