1. 2010

2.  A first degree equation is called a linear equation in two variables if it contains two distinct variables.

3.  1. Arbitrarily select some points that satisfy the equation.  2. Plot the points in a coordinate plane.  3. Draw the line passing through these points. This is the graph of the equation.

4.  Graph y = 2x + 3.

5.  Plotting the x-intercept and y- intercept of a graph and drawing a line through them is called the intercept method of graphing a linear equation.

6.  Graph y = 2x + 4.

7.  Set of two or more equations is called a system of equations.

8.  Consider the following system of equations: y – 2x = –6 y + x = –3 To solve the system, we can first graph each equation.

12.  In order to solve a system of equations we can write the equations in a way that eliminates one of the unknowns. Then the remaining equality will be in one unknown, and we can solve this easily. This method is called the elimination method.

13.  1. Write the given equations in the form Ax + By = C.  2. Take one equation. Make the coefficient of the variable which you want to eliminate the additive inverse of the same variable in the other equation.  3. Add the resulting equations to eliminate your chosen variable.  4. Solve the resulting equation in one unknown.  5. Find the other variable by substituting this solution into either original equation.  6. Check your result.

14.  Another method for solving systems of equations is the substitution method.

15.  1. Solve one of the equations for one variable in terms of the other variable.  2. Substitute the resulting expression into the other equation and solve.  3. Find the other variable by substituting the result of step 2 into either original equation.  4. Check your result.