What does the slope and y-intercept means in this equation?

Question

You have $ 90 to spend on a barbecue where you want to serve chicken and steak. Chicken costs $ 2.00 per pound and steak costs $ 5.00 per pound. Write a function that relates the amounts of chicken and steak you can buy.
After you write the equation that would be 2x+5y=90 then you solve it and it gives you y= -2x+18. What does the slope and y-intercept means in the final equation?

Answer 1

2x+5y=90 gives you

y=-2/5x+18

 

y-intercept is value of y when x is zero. Therefore, it's the pounds of steak you can buy if you don't buy any chicken.

The slope -2/5 indicates that to buy an additional pound of chicken, you have to buy 2/5 less pound of steak or if you bought 1 less pound of chicken, you could buy 2/5 additional pound of steak.