Question

What are the roots of the equation x^2+6x-9=0

Answer 1

Answer:

x = approx. 1.24 or -7.24

Step-by-step explanation:

It's hard to factor directly so we should use the quadratic formula or complete the square. I'm going to go with completing the square.

x²+6x-9=0

x²+6x=9

x²+6x is the same as x²+2·3·x, in order to make this into the algebraic identity (A+B)²=A²+2AB+B², we must add B², or in this case 3² to both sides. (A is x, B is 3)

x²+6x+9=18

(x+3)²= 18

x+3= ±√18

x= ±4.24 -3 (approximately 4.24)

First solution for  x = 4.24-3 = 1.24

Second solution for x = -4.24-3 = -7.24