Solve the following system of equations by using the elimination method. 2x + 4y = 8 and 3x – 3y = 12

  (x, y) = (4, 0)

Step-by-step explanation:

It is convenient to first put the equations into standard form by eliminating common factors. The first equation has a factor of 2 that can be removed; the second equation has a factor of 3 that can be removed. Then you have ...

Subtracting the second equation from the first eliminates the x variable. That gives you ...

  (x +2y) -(x -y) = (4) -(4)

  3y = 0 . . . . . . simplify

  y = 0 . . . . . . . divide by 3

Substituting this value into either equation above, you get ...

  x + 0 = 4

  x = 4

The solution is (x, y) = (4, 0).

Step-by-step explanation:

n=q-9

5n+25q=465, using n from above this becomes

5(q-9)+25q=465

5q-45+25q=465

30q-45=465

30q=510

q=17, and since n=q-9

n=17-9

n=8

So Melinda has 8 nickels and 17 quarters.