Which expression is equivalent to z+(z+6)?

Apool measures 100 meters by 100 meters a toddler inside the pool and trows a ball 60 centimeters from one edge of the pool.how far is the ball from the opposite edge of the pool

Which of the following equations is equivalent to x/3-6/x=1

What is the sum of these mixed numbers 4 2/3+ 3 1/9