What is the slope of the line? –2 – 2

What's the difference between: x≥0 and nonnegative integer. ?

Marco has $38.43 dollars in his checking account. his checking account is linked to his amazon music account so he can buy music. the songs he purchases cost $1.29. part 1: write an expression to describe the amount of money in his checking account in relationship to the number of songs he purchases. part 2: describe what the variable represents in this situation.

Which is f(5) for the function –2x2 + 2x - 3?