Solving a system: graphically Graph both equations. Find the point of intersection if there is one. You may be able to see that the lines are parallel if the slopes match. Therefore there would be no solution.
Graphing Ex. #1 Put both in y = mx+b graph find the point of intersection Check
Graphing Ex. #2 Put both in y = mx+b graph find the point of intersection Check
Solving a system: Substitution 1. Isolate a variable in one of the equations. (Some times done) 2. Substitute one equation into the other. 3. Solve the equation from step 2. 4. Substitute and find the other variable. 5. Check your solution in both equations.
Solving a system: addition 1. Write both equations in standard from, that is ax + by = c 2. possibly us multiplication so when the two equations are added together one variable will cancel out. 3. Add the equations together. 4. Solve the result of step 3. 5. Substitute and find the other variable. 6. Check our solution in all equations
Which method do I choose?! Follow instructions! Graphing is often difficult and not accurate. Substitution is often easy if one variable is already isolated. Addition is often easy if both equations are in standard form.