answer
-625
foil
first foil (20 + 15i)(15i - 20) to get
(20 * 15i) + (20 * (-20)) + (15i * 15i) + (15i * (-20))
= (300i) + (-400) + (225) + (-300i)
combine like terms
combine the i terms together to get
(300i) + (-400) + (225) + (-300i)
300i - 400 + 225 - 300i
= -400 + 225
substitute -1 into i^2
remember that i = so = -1, and substitute this into -400 + 225i^2
-400 + 225i^2
= -400 + 225(-1)
= -400 -225
= -625
7 divided by 1 is 7 so you would do long division
1840 calories. I might be wrong so don't rely on me 100%. Sorry.