Help! I don’t know how to work with slopes

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?

One positive number is 9 more than twice another. if their product is 95, find the numbers

Solve the triangle. a = 21°, c = 105°, c = 5