Question

Solve the equation by completing the square. Round to the nearest hundredth if necessary. x2 – 6x = 20

Answer 1

x^2 – 6x = 20

b=-6

to complete the square, add (b/2)^2 to each side

(b/2)^2 = (-6/2)^2=(-3)^2 =9

x^2 – 6x +9 = 20+9

(x+b/2) ^2 =29

(x-3)^2=29

take the square root of each side

x-3 = +- sqrt (29)

add 3 to each side

x = 3+- sqrt (29)

x = 3 + sqrt(29), x- sqrt(29)

Answer: -2.39, 8.39