Answer:
{x,y} = {400,100}
Step-by-step explanation:
// Solve equation [1] for the variable y
[1] y = -x + 500
// Plug this in for variable y in equation [2]
[2] 5x + 8•(-x +500) = 2800
[2] -3x = -1200
// Solve equation [2] for the variable x
[2] 3x = 1200
[2] x = 400
// By now we know this much :
x = 400
y = -x+500
// Use the x value to solve for y
y = -(400)+500 = 100
