Question

Solve the quadratic equation by completing the square. (Enter your answers as a comma-separated list.) x2 − 6x − 27 = 0

Answer 1

`x^2 - 6x - 27 = 0 \\ \\a=1, \ b=-6 , \ c= -27 \\ \\ \Delta =b^2-4ac = (-6)^2 -4\cdot1\cdot (-27) = 36+108 =144 \\ \\x_(1)=(-b-√(\Delta) )/(2a)=(6-√(144))/(2 )=( 6-12)/(2)=(-6)/(2)=-3 \\ \\x_(2)=(-b+√(\Delta ))/(2a)= (6+√(144))/(2 )=( 6+12)/(2)= (18)/(2)=9 \\ \\ \\ Answer : \ x= -3 \ \ or \ \ x= 9`