Linear Equations In One Variable 8 Class 8 Exam Prep Revision β Grandmaster Guide
Ayush (Founder)
Exam Strategist
- a linear equation β one variable is of the form ax + b = 0, where a β 0
- to solve for x, we use the formula x = -b/a
- we can also represent linear equations β the form x = c, where c is a constant
- for example, 2x = 5 is a linear equation, which can be solved as x = 5/2
- we can also have linear equations β the form x/a = b, which can be solved as x = ab
- for example, x/2 = 3 can be solved as x = 2 Γ 3 = 6
- we can also represent linear equations β the form ax = b, which can be solved as x = b/a
- for example, 3x = 12 can be solved as x = 12/3 = 4
- we can also have linear equations β the form ax + b = c, which can be solved as x = (c - b)/a
- for example, 2x + 3 = 7 can be solved as x = (7 - 3)/2 = 4/2 = 2
πͺ€ The 5 Mistakes That Cost Marks
- not checking if the coefficient of x is zero before solving the equation
- not using the correct formula to solve the equation
- not simplifying the equation before solving for x
- not checking the solution by plugging it back into the original equation
- not writing the final answer β the correct format, for example, x = 2 instead of x = 2.0
βοΈ 3 Solved PYQs
- Question 1: Solve the equation 2x + 5 = 11 step 1: subtract 5 from both sides, we get 2x = 11 - 5 = 6 step 2: divide both sides by 2, we get x = 6/2 = 3 therefore, the solution is x = 3
- Question 2: Solve the equation x/4 = 9 step 1: multiply both sides by 4, we get x = 9 Γ 4 = 36 therefore, the solution is x = 36
- Question 3: Solve the equation x - 3 = 7 step 1: add 3 to both sides, we get x = 7 + 3 = 10 therefore, the solution is x = 10
π§ The One Thing Most Students Get Wrong
- most students get wrong the concept of solving linear equations with variables on both sides
- for example, the equation 2x + 3 = 5x - 2 can be solved by first adding 2 to both sides, we get 2x + 5 = 5x
- then, subtract 2x from both sides, we get 5 = 3x
- finally, divide both sides by 3, we get x = 5/3
- therefore, the solution is x = 5/3
ποΈ Ayush's Note
- to solve linear equations, first simplify the equation by combining like terms
- then, isolate the variable by adding, subtracting, multiplying, or dividing both sides of the equation
- finally, check the solution by plugging it back into the original equation
- for example, to solve the equation 2x + 2 = 6, first subtract 2 from both sides, we get 2x = 4
- then, divide both sides by 2, we get x = 2
- therefore, the solution is x = 2
π Last 5 Minutes Box
- β the last 5 minutes of the exam, quickly review the formulas and concepts of linear equations
- make sure to check the solutions by plugging them back into the original equations
- also, make sure to write the final answers β the correct format
- for example, x = 2 instead of x = 2.0
- quickly review the steps to solve linear equations, such as adding, subtracting, multiplying, or dividing both sides of the equation
π Practice MCQs
1. Question: Solve the equation x + 2 = 9
A) x = 7
B) x = 11
C) x = 10
D) x = 8
Answer: A) x = 7, because subtracting 2 from both sides gives x = 9 - 2 = 7
2. Question: Solve the equation 2x = 12
A) x = 5
B) x = 6
C) x = 4
D) x = 8
Answer: B) x = 6, because dividing both sides by 2 gives x = 12/2 = 6
3. Question: Solve the equation x - 1 = 3
A) x = 2
B) x = 4
C) x = 5
D) x = 6
Answer: B) x = 4, because adding 1 to both sides gives x = 3 + 1 = 4
4. Question: Solve the equation x/3 = 2
A) x = 5
B) x = 6
C) x = 4
D) x = 8
Answer: B) x = 6, because multiplying both sides by 3 gives x = 2 Γ 3 = 6
5. Question: Solve the equation 2x + 1 = 7
A) x = 2
B) x = 3
C) x = 4
D) x = 5
Answer: B) x = 3, because subtracting 1 from both sides gives 2x = 6, then dividing both sides by 2 gives x = 6/2 = 3
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This post was curated by Jules, Exam Compass Bot, and edited for accuracy by Ayush.
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