How to Solve Quadratic Equations in RRB PO Exam?

IBPS RRB PO exam preparation is going on at full speed. This is the time to tackle challenging topics and practice them. These are topics that require a relaxed mind to understand the concepts more effectively. The quadratic equation is one such topic where you need to understand the logic and practice a few tricks so that you can solve the questions in less than a minute.  In this blog, we will decode methods to solve quadratic equations in less time.

What is a Quadratic Equation?

The word quadratic comes from the Latin word quadratus, meaning “square,” because the variable is squared. A quadratic equation is an algebraic equation of the second degree, meaning the highest power of the variable is 2. It is written in the standard form:

ax² + bx + c = 0

where a, b, c are real numbers and a ≠ 0 a, b, c are constants (numbers), x is the variable, and the solutions of this equation are called roots. In the equation, a is called the quadratic coefficient (it must not be zero, otherwise the equation becomes linear). 

How to solve Quadratic Equation in RRB PO Exam?

In this section, we are going to decode the method to solve quadratic equations in RRB PO Exam. 

Factorization Method

It is the most common and quickest method of solving a quadratic equation is the factorisation method. Here are the steps to follow-

1. Multiply a × c
2. Find two numbers whose product = a × c and sum = b
3. Split the middle term and factorise

Example:
x² + 7x + 12 = 0
By applying the steps a=1 b=7 and =12.

a × c = 1×12 =12, sum = 7 as sum = b 

• Product = 12, Sum = 7
• Numbers = 3 and 4
• Roots = -3, -4

Quadratic Formula

If factorisation is not possible, then use this method. It is slightly longer but guarantees the answer. Use the formula given in the image.

Example: 2x² + 3x – 2 = 0

• a = 2, b = 3, c = -2
• Discriminant = b² – 4ac = 9 – (4×2×-2) = 25
• Roots = (-3 ± 5)/4 → (-8/4, 2/4) → -2, 0.5

Completing the Square

This method is less common in exams but helps in understanding.

Example: x² + 6x + 5 = 0

• Move constant: x² + 6x = -5
• Add (b/2)² = 9 both sides: x² + 6x + 9 = 4
• Now: (x+3)² = 4
• Roots = -3 ± 2 → (-1, -5)

RRB PO Special – Comparing Roots

In the RRB PO exam, you’ll often get two quadratic equations and must compare x and y.

Example:

1. x² + 7x + 12 = 0
2. y² + 9y + 20 = 0

• Roots of (1): -3, -4
• Roots of (2): -4, -5

Now compare:

• -3 ≥ -4 and -4 ≥ -5 → So, x ≥ y

Shortcut:

• Sum of roots = -b/a
• Product of roots = c/a
  These help you estimate the range of roots without solving fully.

Download RRB PO Quadratic Equation Question PDF

In this section, we are providing RRB PO quadratic equation question PDF. Solve questions using the methods described above. Try to use a timer while solving questions for better practice.

Download RRB PO Quadratic Equation Question PDF

Time-Saving Tricks for Exams

• If c is positive and b is positive, both roots are negative.
• If c is positive and b is negative, both roots are positive.
• If c is negative, the roots will have opposite signs.
• Use these sign rules to eliminate options quickly in the exam.

Practice Strategy

• Start with easy factorisation problems to build confidence. In the beginning, your focus should be on solving a single question under 40-50 seconds. Always try factorisation first, it’s the fastest method to solve
• If stuck, then use the quadratic formula. Don’t panic if numbers look big; apply the formula calmly. After getting comfortable with factorisation one, move to mixed problems where you must compare roots.
• Finally, practice mock tests to simulate exam speed.  Quadratic equations are high-scoring. With practice, they can become your strongest area.

Conclusion

Quadratic equations in the RRB PO exam are not about memorising formulas; they’re about recognising patterns and applying the right method quickly. With consistent practice, you’ll be able to solve them in seconds and secure marks. To practice more such topic-wise questions, you can take our test series, where you can get such topic-wise tests that are designed as per the exam pattern by our experts after analysing previous year papers. 

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