From the question,
$6.99 is the flat fee/constant fee
$2.99 is the cost per new movie rental.
Let 'x' represent the new movie rental,
Therefore, equation representing the total fee is
[tex]y=2.99x+6.99[/tex]
Thus, the general equation of a line is given as:
[tex]y=mx+b[/tex]
where,
[tex]m=slope[/tex]
Hence, comparing both the general equation with the equation given, the number that represents the slope is
[tex]m=2.99[/tex]
Therefore, the answer is
[tex]\text{ \$2.99}[/tex]
