I need help with part A and part B

LG 6 P2-3 Marginal corporate tax rates Using the corporate tax rate schedule given in Table 2.1, perform the following: a. Find the marginal tax rate for the following levels of corporate earnings before taxes: $15,000; $60,000; $90,000; $200,000; $400,000; $1 million; and $20 million. b. Plot the marginal tax rates (measured on the y axis) against the pretax income levels (measured on the x axis). Explain the relationship between these variables. TABLE 2.1 Corporate Tax Rate Schedule Tax calculation Range of taxable income Base tax + (Marginal rate X amount over base bracket) $ 0 to 0 + X amount over $ 0) (15% (25 amount over (34 amount over to $ 50,000 $ 75,000 100,000 335,000 10,000,000 15,000,000 18,333,333 (39 50,000 to 75,000 to 100,000 335,000 10,000,000 to 15,000,000 to Over 18,333,333 + + + + + amount over 7,500 13,750 22,250 113,900 3,400,000 5,150,000 6,416,667 to (34 amount over 50,000) 75,000) 100,000) 335,000) 10,000,000) 15,000,000) 18,333,333) (35 amount over + (38 X amount over + (35 amount over