Please answer this question

Graph red beads cost $1 an ounce and gold beads cost $3 an ounce. juanita wants to purchase a 12-ounce mixture of red and gold beads that she can sell for $2 an ounce. the solution of the system shows the number of beads needed for juanita to break even. x + y = 12, x + 3y = 24 how many ounces of red beads will juanita buy to break even? how many ounces of gold beads will she buy?

Another type of subtraction equation is 16-b=7. explain how you would sole this equation then solve it.

The perimeter of a rectangle is 42 inches. if the width of the rectangle is 6 inches, what is the length