Answer:
The solution to the equation is x = 0.38 or -18.38
Step-by-step explanation:
x^2+18x=7 can be properly written as
[tex]x^{2} +18x =7[/tex]
To solve by completing the square, divide the coefficient of x by 2, square and then add to both sides
i.e 18/2 = 9
Then add 9² to both sides of the equation
[tex]x^{2} +18x + 9^{2} = 7 + 9^{2}[/tex]
This becomes
[tex](x+9)^{2} = 7 + 81[/tex]
[tex](x+9)^{2} = 88[/tex]
[tex]x+9 = \pm \sqrt{88}[/tex]
[tex]x = -9 \pm\sqrt{88}[/tex]
[tex]x = -9 \pm 9.38[/tex]
∴ [tex]x = -9+9.38 or -9-9.38[/tex]
[tex]x = 0.38 or -18.38[/tex]
Hence, x = 0.38 or -18.38
