Review the steps of the proof of the identity Sine (A minus StartFraction 3 pi Over 2 EndFraction) = cosine A. Sine (A minus StartFraction 3 pi Over 2 EndFraction)

Step 1: = Sine A cosine (StartFraction 3 pi Over 2 EndFraction) minus cosine A sine (StartFraction 3 pi Over 2 EndFraction)

Step 2: = (Sine A) (0) + cosine A (negative 1)

Step 3: = (Sine A) (0) + (1) (cosine A)

Step 4: = 0 + cosine A

Step 5: Cosine A

At which step was an error made?

step 1
step 2
step 3
step 4

mr. flanders’ class sold 47 doughnuts and   mr. rodriquez’s class sold 38 cartons of milk

step-by-step explanation:

let x be the number of doughnuts sold by mr. flanders’ class and y be the number of cartons sold by mr. rodriquez’s class.

1. together, the classes sold 85 items, then

x+y=85.

2. both classes earn earned $104.49 for their school. if doughnuts were sold for $1.35 each, then x doughnuts costed $1.35x. if cartons of milk were sold for $1.08 each, then y cartons costed $1.08y. hence,

1.35x+1.08y=104.49.

3. solve the system of two equations:

21

step-by-step explanation: