Quadratic Equation Shortcut Tricks for Bank Exams: Sign Table + Quiz

Last updated: June 27, 2026. For coaching and doubts, contactShortcut Maths, Jadavpur, Kolkata 700032. Call+91-9804490328.

The Sign Table Trick (Roots from Equation Signs)

For any quadratic equation x² + bx + c = 0, the roots follow this pattern:

Why it works: In x² − (sum)x + product = 0, if the product c is positive, both roots share the same sign. If c is negative, the roots have opposite signs.

Product-Sum Split Method

To factor x² + bx + c, find two numbers p and q such that:

Then the roots are simply −p and −q (when signs are standard).

Need p × q = 12 and p + q = 7. Numbers: 3 and 4. Roots: 3 and 4.

Need p × q = −24 and p + q = 5. Numbers: 8 and −3. Roots: −8 and 3 (because equation sign pattern gives one negative root).

p × q = c (constant term)
p + q = b (middle coefficient)

Splitting Large Numbers Instantly

When c is large, list factor pairs of c quickly using divisibility rules:

5-Question Practice Quiz

Solve these in under 2 minutes. Compare roots of both equations.

x² − 9x + 20 = 0 vs y² − 13y + 42 = 0
x² + 7x − 60 = 0 vs y² − 5y − 84 = 0
x² − 17x + 72 = 0 vs y² − 19y + 88 = 0
x² + 11x + 28 = 0 vs y² + 15y + 56 = 0
x² − 31x + 228 = 0 vs y² − 29y + 210 = 0

Answer Key

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FAQs

Usually 5 questions from one set of quadratic comparisons.

Divide or multiply to make the coefficient of x² equal to 1 first.

Divide the entire equation by a to convert it to standard form, then apply the sign table.

Last updated: June 27, 2026. For Bank PO coaching in Kolkata, call +91-9804490328.

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