Answer:
(a+c)+7
Step-by-step explanation:
this is called the Associative Property
(x+y)+z=x+(y+z)
For this case we have the following data:


So that the figure can be a rectangle, its diagonals must be equal, that is, 
In this way we have:

Clearing x we have:


Thus, x must be equal to 10 so that the figure is a rectangle.
Answer:

Option A
Answer:
it is 20 pairs count them 1 Collin and its 20
Answer:
<h3>C. (a, b)</h3>
Step-by-step explanation:
The formula of a midpoint:

We have A(0, 0) and C(2a, 2b). Substitute:

M(a, b)