Solve the equation by completing the square. Round to the nearest hundredth if necessary. x2 - 4x = 5

Solve for x over the real numbers:

x^2 - 4 x = 5

Subtract 5 from both sides:

x^2 - 4 x - 5 = 0

x = (4 ± sqrt ((-4) ^2 - 4 (-5))) / 2 = (4 ± sqrt (16 + 20)) / 2 = (4 ± sqrt (36)) / 2:

x = (4 + sqrt (36)) / 2 or x = (4 - sqrt (36)) / 2

sqrt (36) = sqrt (4*9) = sqrt (2^2*3^2) = 2*3 = 6:

x = (4 + 6) / 2 or x = (4 - 6) / 2

(4 + 6) / 2 = 10/2 = 5:

x = 5 or x = (4 - 6) / 2

(4 - 6) / 2 = - 2/2 = - 1:

Answer: x = 5 or x = - 1