The additional property of equality says that whatever is added to one side of the equation must be added to the other side

If i have one apple and give you the apple, how many apples do i have?

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)

Aprojectile is thrown upward so that its distance above the ground after t seconds is given by the function h(t) = -16t2 + 704t. after how many seconds does the projectile take to reach its maximum height?