One federal tax schedule states that if you are single and your taxable income is between $37,450 and $90,750, then you owe $5156.25 plus 25%
of your taxable income over $37,450. Is the tax you owe a linear function of your taxable income if the taxable income is between $37,450 and $90,750?
If so, find a formula giving tax owed as a linear function of taxable income over $37,450.