Which fraction is equivalent to 7/21

Match each function with the corresponding function formula when h(x) = 5 - 3x and g(x) = -3 x + 5. 1. k(x) = (3g + 5h)(x) 2. k(x) = (h - g)(x) 3. k(x) = (g + h)(x) 4. k(x) = (5g + 3h)(x) 5. k(x) = (3h - 5g)(x) 6. k(x) = (5h - 3g)(x)