Help me please i dont understand

Janet is mixing a 15% glucose solution with a 35% glucose solution. this mixture produces 35 liters of a 19% glucose solution. how many liters of the 15% solution is januet using in the mixture? a. 25 liters c. 28 liters b. 7 liters d. 10 liters

Solve the equation using the zero-product property. -3n(7n - 5) = 0 a. 0, -5/7 b. -1/3, -5/7 c. -1/3, 5/7 d. 0, 5/7

Suppose a gym membership has an initial enrollment fee of $75 and then a fee of $29 a month. which equation models the cost, c, of the gym membership for m months?