The expression I found in question number 3 is 141x^2 - 200x + 47

Given the expression
[tex]141x^2-200x+47[/tex]a) The area of the grass if x=8 feet is:
Substitute x = 8 in the above expression
[tex]area=141(8)^2-200(8)+47[/tex]Calculate exponents
[tex]\text{area}=141(64)-200(8)+47[/tex]Multiply
[tex]\text{area}=9024-1600+47[/tex]Subtract 9024 - 1600
[tex]\text{area}=7424+47[/tex]And add 47
[tex]\text{area}=7471[/tex]Answer: area = 7471 ft^2
b) Answer: The area of the grass is 7471 square feet.