Question

Solve the equation p^2 + 4p = 1 by completing the square.

Answer 1

p = -2 ±sqrt( 5)

Explanation:

p^2 + 4p = 1

Take the coefficient of p

4

Divide by 2

4/2 =2

Square it

2^2 = 4

Add it to each side

p^2 + 4p+4 = 1+4

(p+2) ^2 = 5

Take the square root of each side

sqrt((p+2) ^2) =±sqrt( 5)

p+2 = ±sqrt( 5)

Subtract 2 from each side

p+2-2 = -2 ±sqrt( 5)

p = -2 ±sqrt( 5)