I believe all you do is add the numbers with the same coefficients so 2x + 5x + x (in front of x is understood to be a 1) So you get 8x. And 8 + 1 is 9 so the perimeter is B. 8x + 9
Answer: A linear equation in two variables can be described as a linear relationship between x and y, that is, two variables in which the value of one of them (usually y) depends on the value of the other one (usually x). In this case, x is the independent variable, and y depends on it, so y is called the dependent variable.
Given:
A circle with radius 7 units and chord CD = 7 units.
To find:
The measure of arc CD.
Solution:
Let O be the center of the circle.
In triangle OCD,
(Given)
(Radii of same circle)
(Given)
Since 
all sides are equal, therefore, the triangle OCD is an equilateral triangle.
Measure of each angle of an equilateral triangle is 60 degrees. So,
The measure of central angle is equal to the measure of corresponding arc.
Therefore, the measure of arc CD is 60 degrees.
I guess you multiply everything times "x", the Xs cancel out, then you will have " a + b = 1x " basically the one does not make any change, so you will end with a " a + b = x "
