X squared plus 2x equals 9?

Answer 1

x2+2x=9 we can complete the square or use the quadratic formula. Let's complete the square. add 2/2=1 to both sides and we ahve x2+2x+1=10 now factor the left side and use the square root property (x+1)2=10 so x+1= plus of minus the square root of 10 x=- 1+ or - square root of 10 using the quadratic formula we have a=1, b=2 and c=-9 so [-2+ or - (square root of (4+36))]/2= -1 + or - square root of 10 as we had before.