I need help with my math homework!

Answer:
Exercise 2)
(6y^2 - 10y)
Exercise 3)
25$
Exercise 4)
y = x + 5
Step-by-step explanation:
Exercise 2)
(3y - 5) * 2y = 6y^2 - 10y
Exercise 3)
30 * m (Months) + 25
Exercise 4)
3x - 3y = 15 (divide by 3)
x - y = 5 (-x and multiply by (-1))