How do you find the square root of a number?

Tom can paint the fence in 12 hours, but if he works together with a friend they can finish the job in 8 hours. how long would it take for his friend to paint this fence alone?

The owner of the plant nursery where you were tells you to fill 350 ml bottles from a 30 l from a fertilizer

Whats are the trickiest steps to do when adding or subtracting rational expressions? how does knowledge of rational numbers u in adding and subtracting rational expressions?