I would approach this from a Guess and Check Strategy. Take combinations of two numbers when added equal six: 0 + 6 1+ 5. 2+ 4, 3 + 3, 4 + 2, 5 + 1, 6 + 0. Take a combination like 3 + 3. If the student bought 3 notebooks at $8 each and 3 notebooks at $10 each it would be $24 + $30 = $54 which is just short of $56. You could use each of the combinations in the same way until you match $56. In the end the combination of 2 + 4 would solve the problem. Two notebooks at $8 each plus four notebooks at $10 each would be: $16 + $40 which does equal $56. So the student bought 2 notebooks at $8 each and 4 notebooks at $0 each.
The first thing you have to do is find a way to make the last digit 6 (since its $56). So that would be $8×2=16, so there are 2 small notebooks. Then, she needs another $40 to get $56, so 40÷10=4, so she bought 4 large notebooks.
you need to combine everything that does not have an exponent (example. a, x, y) and you combine the ones that have exponents together. and therefore you get 6y-6 (remember positive and negative signs)
