In 2014, Jeff, who is single, is entitled to the following deductions before phase-outs: State income taxes

Question:

In 2014, Jeff, who is single, is entitled to the following deductions before phase-outs:
State income taxes ..................................... $7,850
Real estate taxes ........................................ 1,900
Home mortgage interest ............................... 8,200
Charitable contributions ............................... 1,700
a. Assume that Jeff's AGI is $280,000. Calculate Jeff's itemized deductions after considering the overall phase-out of itemized deductions.
b. Suppose that Jeff's AGI increases to $1,280,000. Calculate Jeff's itemized deductions after considering the overall phase-out of itemized deductions.