Setimate the value of the numbet below to the nearest wholr number

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.

Does anyone know how to do geometryme with this problem

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?