Worksheet on Linear Equations
Investigate and Explain the Different Number of Solutions an Equation Can Have
Question 1
Equations:
- Equation A: \(2x + 3 = 2x + 5\)
- Equation B: \(x + 2 = x + 2\)
- Equation C: \(3x - 5 = 2x + 1\)
- Equation D: \(5x + 1 = 5x + 3\)
- Equation E: \(4x - 1 = 2x + 5\)
- Equation F: \(6 - x = x + 2\)
-
Infinite Solutions (circled):
- Equation B: \(x + 2 = x + 2\) (This simplifies to a true statement for all \(x\), hence infinite solutions.)
- Equation E: \(4x - 1 = 2x + 5\) (This results in consistent values of all solutions.)
-
No Solutions (squared):
- Equation A: \(2x + 3 = 2x + 5\) (Subtracting \(2x\) gives \(3 = 5\), which is a contradiction.)
- Equation D: \(5x + 1 = 5x + 3\) (Subtracting \(5x\) gives \(1 = 3\), which is also a contradiction.)
-
One Solution (underlined):
- Equation C: \(3x - 5 = 2x + 1\) (Solving yields \(x = 6\).)
- Equation F: \(6 - x = x + 2\) (Solving yields \(x = 2\).)
Question 2: Infinite Solutions
Equations:
-
Equation B: \(x + 2 = x + 2\)
-
Equation E: \(4x - 1 = 2x + 5\)
-
Solving Equation E:
- \(4x - 1 = 2x + 5\)
- \(4x - 2x = 5 + 1\)
- \(2x = 6 \Rightarrow x = 3\)
Notice About Equations: Both equations are either identical (B) or can be transformed into the same line (E), which means they share all values along that line.
What it Means to Have Infinite Solutions: It means that every value of \(x\) that satisfies one equation also satisfies the other, indicating that they are the same line in a geometric sense.
Plugging in Values
-
For \(x = 3\):
- Equation B: LHS = \(3 + 2 = 5\); RHS = \(3 + 2 = 5\) (True)
- Equation E: LHS = \(4(3) - 1 = 11\); RHS = \(2(3) + 5 = 11\) (True)
-
For \(x = -2\):
- Equation B: LHS = \(-2 + 2 = 0\); RHS = \(-2 + 2 = 0\) (True)
- Equation E: LHS = \(4(-2) - 1 = -9\); RHS = \(2(-2) + 5 = 1\) (False)
Question 3: No Solutions
Equations:
-
Equation A: \(2x + 3 = 2x + 5\)
-
Equation D: \(5x + 1 = 5x + 3\)
-
Solving Equation A:
- \(2x + 3 = 2x + 5\)
- Subtract \(2x\) from both sides gives: \(3 = 5\) (Contradiction)
-
Solving Equation D:
- \(5x + 1 = 5x + 3\)
- Subtract \(5x\) gives: \(1 = 3\) (Contradiction)
What it Means to Have No Solutions: This means the lines are parallel and will never intersect, thus no value satisfies both equations.
Plugging in Values
-
For \(x = 2\):
- Equation A: LHS = \(2(2) + 3 = 7\); RHS = \(2(2) + 5 = 9\) (False)
- Equation D: LHS = \(5(2) + 1 = 11\); RHS = \(5(2) + 3 = 13\) (False)
-
For \(x = -3\):
- Equation A: LHS = \(2(-3) + 3 = -6 + 3 = -3\); RHS = \(2(-3) + 5 = -6 + 5 = -1\) (False)
- Equation D: LHS = \(5(-3) + 1 = -15 + 1 = -14\); RHS = \(5(-3) + 3 = -15 + 3 = -12\) (False)
Question 4: One Solution
Equations:
-
Equation C: \(3x - 5 = 2x + 1\)
-
Equation F: \(6 - x = x + 2\)
-
Solving Equation C:
- \(3x - 5 = 2x + 1\)
- Rearranging gives: \(x = 6\)
-
Solving Equation F:
- \(6 - x = x + 2\)
- Rearranging gives: \(2x = 4 \Rightarrow x = 2\)
What it Means to Have One Solution: This indicates that the two lines intersect at exactly one point, meaning there’s exactly one value for \(x\) that satisfies both equations.
Plugging in Values
Plugging \(x = 6\):
- Equation C: LHS = \(3(6) - 5 = 18 - 5 = 13\), RHS = \(2(6) + 1 = 12 + 1 = 13\) (True)
- Equation F: LHS = \(6 - 6 = 0\), RHS = \(6 + 2 = 8\) (False)
Plugging \(x = 4\) (to show it is not a solution):
- Equation C: LHS = \(3(4) - 5 = 12 - 5 = 7\), RHS = \(2(4) + 1 = 8 + 1 = 9\) (False)
- Equation F: LHS = \(6 - 4 = 2\), RHS = \(4 + 2 = 6\) (False)
Question 5: Writing Linear Equations
Infinite Solutions Example:
- Equations:
- \(2x + y = 4\)
- \(4x + 2y = 8\)
(These are multiples of each other.)
No Solution Example:
- Equations:
- \(x - y = 2\)
- \(x - y = 4\)
(These are parallel lines.)
One Solution Example:
- Equations:
- \(x + y = 10\)
- \(2x + y = 12\)
(These lines intersect at one point, \(x = 2\), \(y = 8\).)
Real-World Scenario: Two friends are each saving money to buy bikes.
- Friend 1 saves $5 per week: \(y = 5x\).
- Friend 2 saves $10 per week but started with $10: \(y = 10x + 10\).
If both save for the same number of weeks \(x\), set \(5x = 10x + 10\) to find \(x\) where they meet their targets, demonstrating one solution exists.
Feel free to adjust the content further or contact me for any clarifications or additional problems!