X=2y-1 3x-3y=9
a. substitution; (7,4)
b. elimination using multiplication; (3, 2)
C. substitution; (4,7)
d. elimination using multiplication; -21,-10)

Substitution (7,4)

Step-by-step explanation: Since the value of X is given to us, just plug that in to the other equation to solve for the y coordinate.

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: