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What does it mean when solving a system of equations results in an identity or a contradiction?
One solution.
To determine how many solutions this system has, we will solve it by substitution. Doing so will result in one of three cases.
| Result of solving by substitution | Number of solutions |
|---|---|
| A value for x and y is determined. | One solution |
| An identity is found, such as 2=2. | Infinitely many solutions |
| A contradiction is found, such as 2≠3. | No solution |
This means that we should solve the given system of equations and make our conclusion based on the result.
When solving a system of equations using substitution, there are three steps.
Consider the given equations, we need to isolate one of the variables. Let's start by isolating 3x in Equation I.
(I): LHS * 2=RHS* 2
(I): LHS-4y=RHS-4y
Now that we've isolated 3x, we can solve the system by substitution.
(II): 3x= 22-4y
(II): Add terms
(II): LHS-22=RHS-22
(II): .LHS /2.=.RHS /2.
Now, to find the value of x, we need to substitute y=0 into either one of the equations in the given system. Let's use the first equation.
(I): y= 0
(I): Zero Property of Multiplication
(I): .LHS /3.=.RHS /3.
Solving this system resulted in the values x= 223 and y=0. This is the one solution to this system.