Here, we observe that 10 is added to a giving the number 10 itself as the answer. So, we know of a property which says that when 0 is added to a number, the result is the number itself.This property is called identity property of addition.
So, the value of must be 0 because on adding to 10, we are getting the number 10 only. So, the above statement is an example of identity property of addition.
Distributive property means that you have to multiply everything directly outside the parent hes to everything inside the parentheses. For this problem multiply 7 to the 9x and to the -9 like so:
Given that the distance d, in centimeters, that a diving board bends below its resting position when you stand at its end is dependent on your distance x, in meters, from the stabilized point