Algebra I Recipe: Graphing Linear Equations with Two Variables
By G Redden
A. How to Determine if a Given Point is a Solution to a Given Equation
- Substitute the x and y values from the ordered pair into the equation for x and y.
- Perform all operations until a true or false statement can be determined.
- If a true statement is the result, then the point is a solution to the equation.
- If a false statement is the result, then the point is NOT a solution to the equation.
- If an ordered pair is a solution to an equation, then the point would lie on the graph of the equation.
1.
Is (-1, -7) a solution to 6x - 2y = 8?
2.
Is (-1, -1) a solution to –2x - 9y = 7?
3.
Is (-2, 8) a solution to 2y - 4x = 8?
4.
Is (2, -1) a solution to 6y - 3x = -9?
B. Graphing a Linear Equation using the “Box Method” (or table of values)
- Draw a box with a vertical x column, a vertical equation column, a vertical y column, and a vertical (x,y) column.
- Choose –2, -1, 0, 1, 2 for x into the box.
- Substitute these x-values into the equation one at a time.
- Solve the equation for y for each different x-value and put the y-values you obtain into the box.
- Five ordered pairs or points have been found.
- Graph the five points.
- Connect the points with a straight line with arrows on each end.
- Label the line with its equation.
5.
y = -2x + 5
6.
y = -(3 - x)
7.
y = -¾x + 1
8.
x - 2y = 6
9.
x = 9
10.
y = -1
