College Algebra
posted by Bobbie .
The value of the expression (4220 + 0.25 (x  30,650) is the 2006 federal income tax for a single taxpayer with taxable income of x dollars, where x is over $30,650 but not over $74,200. Simplify the expression; Find the amount of tax for a single taxpayer with taxable income of $40,000. Who pays more, a married couple with a joint taxable income of $80,000 or two single taxpayers with taxable income of $40,000 each?

Find the amount of tax for a single taxpayer with taxable income of $40,000.
Let x = 40,000 in the expression and simplify.
4420 + 0.25 (40,000  30,650)
4420 + 0.25(9350)
4420 + 2337.5 = $6757.5...assuming that you placed your parentheses correctly in the expression above.
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The question tells us that "...x is over $30,650 but not over $74,200.
So, the expresison given cannot be applied to the married couple because their taxable income is over $74.200.
For two single taxpayers with taxable income of $40,000, we just found out that one single taxpayer will be taxed
$6757.5 and so, if you multiply $6757.5 times 2 you will a total tax of
$13,515.
I would say that since $80,000 does not apply to the given formula, two single taxpayers whose taxable income is $40,000 will pay less than a married couple or a single person whose taxable income is greater than $74,200.
I hope this helps.