You can have a maximum of 3 groups. This is due to the fact that you only have 3 sopranos to equally divide between groups. Over 3 you would have a group lacking a soprano so 3 is the greatest you can make it.
So to solve for y, we need to get y alone on one side of the equation. So we are going to subtract 9x from both sides of the equation to get:

And since y is negative, we are going to divide both sides by -1 in order to make the y positive:

Answer:
A
Step-by-step explanation:
it's A because if you're adding x from each number in the equation you would shift to the left causing the graph to become more positive but if you subtract x you would shift to the right causing the graph to become more negative.