Presentation on theme: "Solving Systems of Equations"— Presentation transcript:
1 Solving Systems of Equations 3 ApproachesClick here to beginMs. NongAdapted from Mrs. N. Newman’s PPT
2 Method #1GraphicallyPOSSIBLE ANSWER:Answer: (x, y)or (x, y, z)Method #2Algebraically Using Addition and/or SubtractionAnswer: No SolutionAnswer: IdentityMethod #3Algebraically Using Substitution
3 In order to solve a system of equations graphically you typically begin by making sure both equations are in Slope-Intercept form.Where m is the slope and b is the y-intercept.Examples:y = 3x- 4y = -2x +6Slope is 3 and y-intercept is - 4.Slope is -2 and y-intercept is 6.
5 Looking at the System Graphs: If the lines cross once, therewill be one solution.If the lines are parallel, therewill be no solutions.If the lines are the same, therewill be an infinite number of solutions.
7 In order to solve a system of equations algebraically using addition first you must be sure that both equation are in the same chronological order.Example:Could be
8 Now select which of the two variables you want to eliminate. For the example below I decided to remove x.The reason I chose to eliminate x is because they are the additive inverse of each other. That means they will cancel when added together.
9 Now add the two equations together. Your total is:therefore
10 I decided to substitute 3 in for y in the second equation. Now substitute the known value into either one of the original equations.I decided to substitute 3 in for y in the second equation.Now state your solution set always remembering to do so in alphabetical order.[-1,3]
11 Lets suppose for a moment that the equations are in the same sequential order. However, you notice that neither coefficients are additive inverses of the other.Identify the least common multiple of the coefficient you chose to eliminate. So, the LCM of 2 and 3 in this example would be 6.
12 Multiply one or both equations by their respective multiples Multiply one or both equations by their respective multiples. Be sure to choose numbers that will result in additive inverses.becomes
13 Now add the two equations together. becomesTherefore
14 Now substitute the known value into either one of the original equations.
15 Now state your solution set always remembering to do so in alphabetical order. [-3,3]
16 In this example it has been done for you in the first equation. In order to solve a system equations algebraically using substitution you must have one variable isolated in one of the equations. In other words you will need to solve for y in terms of x or solve for x in terms of y.In this example it has been done for you in the first equation.
17 Choosing to isolate y in the first equation the result is : Now lets suppose for a moment that you are given a set of equations like this..Choosing to isolate y in the first equation the result is :
18 Now substitute what y equals into the second equation. becomesBetter know asTherefore
19 Lets look at another Systems solve by Substitution
20 Step 5: Check the solution in both equations. y = 4x3x + y = -21Step 5: Check the solution in both equations.3x + y = -213(-3) + (-12) = -21-9 + (-12) = -21-21= -21y = 4x-12 = 4(-3)-12 = -12
21 This concludes my presentation on simultaneous equations. Please feel free to view it again at your leisure.