1. Graphs of Equations in Two Variables
The solution of an equation is the set of all of the ordered pairs that make the equation true.
Ex 1: Use a t-chart to graph:
Ex 2: Use a t-chart to graph:
Ex 3: Use a t-chart to graph:

2. Intercepts
An x-intercept is a point where a graph of an equation intersects the x-axis. (a,0)
An y-intercept is a point where a graph of an equation intersects the y-axis. (0,b)
Ex 4: Find the intercepts of:
y-intercept: (0,3); x-intercepts: (-3,0) and (1,0)

3. Equation of a Circle
If a circle is centered at (h,k) with a radius of r, then the standard form of its equation is:
Ex 5a: Graph:
Ex 5b: Graph:

4. Ex 6a: Find the equation of a circle with center
(-5,6) and a radius of 9.
Ex 6b: Find the equation of a circle with a diameter with endpoints (-5,6) and (1,8).
Ex 7: Rewrite this equation in standard form.

5. Symmetry
To test for symmetry with respect to the x – axis, we check to see if the equation is unchanged when y is replaced by -y.
To test for symmetry with respect to the y – axis, we check to see if the equation is unchanged when x is replaced by -x.
To test for symmetry with respect to the origin, we check to see if the equation is unchanged when x is replaced by -x and y is replaced by -y.

6. Ex 8: Test the equation for symmetry and sketch:
Symmetric with respect to the x-axis.
Ex 9: Test the equation for symmetry and sketch:
Symmetric with respect to the x-axis, y-axis, and origin.

7. Assignment S 2.2:
pg 167
#7-10,12,16,17,28,34,40