Answer:
[tex]x^2+x+8x=(x+\frac{9}{2} )^2-\frac{81}{4}[/tex]
Step-by-step explanation:
The given expression is [tex]x^2+x+8x[/tex]
To complete the square, we first simplify the function to get:
[tex]x^2+9x[/tex]
Add and subtract the square of half the coefficient of x
[tex]x^2+9x+(\frac{9}{2} )^2-(\frac{9}{2} )^2[/tex]
The first three term is a perfect square [tex](x+\frac{9}{2} )^2-\frac{81}{4}[/tex]