If the mpc=.77 and the government cuts spending by $21 billion, how much will AD shift? (negative numbers to the left; positive numbers to the right. Only number, no words or $. Round to the nearest tenth (3.6))

If the mpc=.83 and the government cuts taxes by $61 billion, how much will AD shift? (negative numbers to the left; positive numbers to the right. Only number, no words or $)