Question

Salim has 9 five-dollar bills and ten-dollar bills in his

Answer 1

As you can see, you either simplify the x + y equation to get y = -x + 9 or x = -y + 9, and then plug it into the other question to do substitution (shown in visual), or you could do elimination, where you make either the x or y value from one equation, such as x + y = 9, and form it into an equation so that either x or y can cancel out the other x or y in the other equation. For example, you could make -5x + -5y = -45 to cancel out the 5x, and simplify from there. You can always check your work and see that y (3) times 10 is 30, and x (6) times 5 is also 30, adding up to 60. Hope this helped!