Solve equation by completing the square x^2+9x+c

Question

X^2 +9x+c

Answer 1

Mark M. is right. 

 

 

Assuming you meant x^2 + 9x + c = 0 is the equation

 

You can complete the square as follows:

 

x^2 + 9x + (9/2)^2 -(9/2)^2 +c = 0

 

(x+9/2)^2 -(9/2)^2 + c = 0

 

(x+9/2)^2 = (9/2)^2 -c

 

(x+4.5)^2 = 4.5^2 -c

 

x+4.5 = +/- sqrt (4.5^2 -c)

 

x = -4.5 +/- sqrt(4.5^2 - c)