Torri had$20 to buy a birthday persent for her dad she decided to buy a dvd for $18 the sales tax is $7 does she have enogh money

If f(x) = 3-2x and g(x) =1/x+5 to what is the value (f/g)(8)

Pls! does anybody know a shortcut for answering these types of questions in the future?

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?