1.3n-0.03=-9 (solve for n) grade lvl. 7

Hello from MrBillDoesMath!

-6.9

Discussion:  

1.3n - 0.03 = -9     =>              multiply both sides by 100

130n - 3 = -900 =>

130n = -900 +3 =  -897 =>     add 3 to both sides

n = -897/130  =>

n =  - (69 * 13)/ (10*13) =>

n = - 69/10 = - 6.9

Thank you,

MrB

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: