5y + 3x = 3 -8y + 9x = -12 solve for x and y

x = -4 , y = -3

Step-by-step explanation:

Solve the following system:

{3 x - 5 y = 3 | (equation 1)

9 x - 8 y = -12 | (equation 2)

Swap equation 1 with equation 2:

{9 x - 8 y = -12 | (equation 1)

3 x - 5 y = 3 | (equation 2)

Subtract 1/3 × (equation 1) from equation 2:

{9 x - 8 y = -12 | (equation 1)

0 x - (7 y)/3 = 7 | (equation 2)

Multiply equation 2 by 3/7:

{9 x - 8 y = -12 | (equation 1)

0 x - y = 3 | (equation 2)

Multiply equation 2 by -1:

{9 x - 8 y = -12 | (equation 1)

0 x+y = -3 | (equation 2)

Add 8 × (equation 2) to equation 1:

{9 x+0 y = -36 | (equation 1)

0 x+y = -3 | (equation 2)

Divide equation 1 by 9:

{x+0 y = -4 | (equation 1)

0 x+y = -3 | (equation 2)

Collect results:

 {x = -4 , y = -3

distance covered by pamela in 9 l of fuel = 99km

let us apply unitary method here.

distance covered by pamela in 1 l of fuel =99/9 =11 km

now let us find distance covered by pamela if she has 12 l of fuel.

distance covered in 12 l = distance covered in 1 l of fuel * 12

we know that distance covered by here in 1 l is 11 km.

so distance covered in 12 l of fuel = 11*12 = 132 km.

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: