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Introduction
Mathematics has always been a subject of curiosity, logic, and problem-solving. Among all algebraic concepts in Class 10, the chapter on Quadratic Equations (Chapter 4, NCERT) is considered one of the most important. Not only does it carry high weightage in board exams, but it also plays a key role in competitive exams like NTSE, Olympiads, and later in JEE/NEET preparation.
At FUZY MATH ACADEMY, we believe that students from Classes 5 to 12 deserve the best online learning experience powered by an AI-enabled LMS and 24/7 chatbot support. With our smart teaching methods, live + recorded lectures, and instant doubt-solving tools, learning Quadratic Equations becomes simple, effective, and engaging.
In this blog, let’s understand Quadratic Equations step-by-step, with definitions, formulas, applications, and 20 important NCERT-based questions with solutions.
📑What is a Quadratic Equation?
A quadratic equation in one variable is an equation of the form:
Where:
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are real numbers
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(since otherwise it becomes a linear equation)
Example:
👉Methods of Solving Quadratic Equations
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Factorization Method
Break the middle term and solve by splitting into two linear factors. -
Completing the Square Method
Convert the equation into a perfect square and then solve. -
Quadratic Formula Method
Using the formula:
Here, the term is called the Discriminant (D).
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If 2 distinct real roots
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If 2 equal real roots
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If : No real roots
🔍Real-Life Applications of Quadratic Equations
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Calculating areas of plots
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Projectile motion problems in physics
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Maximum profit and minimum cost in business
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Motion problems (time & distance)
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Designing architecture and bridges
📌Why Students Struggle with Quadratic Equations
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Confusion in formula application
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Mistakes in sign while solving
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Lack of practice in word problems
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Not understanding discriminant properly
💬At FUZY MATH ACADEMY, these challenges are solved with:
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Step-by-step LMS tutorials
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Instant practice quizzes
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AI-chatbot for immediate doubt solving
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Real-world examples to boost clarity
💎20 Important NCERT-Based Questions with Solutions
Quadratic Equations – Important Questions with Solutions
x2 − 5x + 6 = 0
x2 − 5x + 6 = (x−2)(x−3)
.x−2=0 ⇒ x=2
and x−3=0 ⇒ x=3
.x = 2, 3
2x2 − 7x + 3 = 0
D = b2 − 4ac = (−7)2 − 4·2·3 = 49 − 24 = 25
.x = [7 ± √25] / (2·2) = (7 ± 5)/4
.x = 3
or x = 1/2
.x2 − 2x − 15 = 0
x2 − 5x + 3x − 15 = (x−5)(x+3)
.x = 5, −3
.x2 + 4x + 5 = 0
D = 42 − 4·1·5 = 16 − 20 = −4
.D < 0
, no real roots (roots are complex).n
. Then n(n+1)=306
.n2 + n − 306 = 0
. Solve using quadratic formula or factorization.1 + 4·306 = 1 + 1224 = 1225 = 352
.n = [−1 ± 35]/2
⇒ positive root n = (34)/2 = 17
.17
and 18
.3x2 − 5x + 2 = 0
D = (−5)2 − 4·3·2 = 25 − 24 = 1
.x = [5 ± 1] / (2·3) = (5 ± 1)/6
⇒ x = 1
or x = 2/3
.x = 1, 2/3
.2x2 − 4x + 2 = 0
D = (−4)2 − 4·2·2 = 16 − 16 = 0
.x = 4 / (2·2) = 4/4 = 1
.x = 1
(equal roots).n
then n2 + (n+1)2 = 365
.n2 + n2 + 2n + 1 = 365 ⇒ 2n2 + 2n − 364 = 0 ⇒ n2 + n − 182 = 0
.1 + 728 = 729 = 272
. So n = (−1 ± 27)/2
⇒ positive root n = 13
.13
and 14
.x2 − 8x + 12 = 0
(x−6)(x−2) = 0
.x = 6, 2
.6x2 − 11x − 35 = 0
D = (−11)2 − 4·6·(−35) = 121 + 840 = 961 = 312
.x = [11 ± 31] / (2·6) = (11 ± 31) / 12
. So x = 42/12 = 7/2
or x = −20/12 = −5/3
.x = 7/2, −5/3
.b
, length = l = b + 6
. Then b(b+6)=54
.b2 + 6b − 54 = 0
. Discriminant D = 62 − 4·1·(−54) = 36 + 216 = 252
.√252 = √(36·7) = 6√7
. So b = [−6 ± 6√7]/2 = −3 ± 3√7
. Take positive: b = −3 + 3√7
.l = b + 6 = 3 + 3√7
(approx values: b ≈ 4.937
, l ≈ 10.937
).b = −3 + 3√7
, l = 3 + 3√7
.x2 + 7x + 12 = 0
(x+3)(x+4) = 0
.x = −3, −4
.x2 − 2x − 8 = 0
(x−4)(x+2)=0
.x = 4, −2
.r
and 2r
. Sum = 3r = 9 ⇒ r = 3
.−b/a = 9
and product = 18 ⇒ c/a = 18
.a = 1
→ equation: x2 − 9x + 18 = 0
.3, 6
. Equation: x2 − 9x + 18 = 0
.2x2 − 9x + 7 = 0
D = (−9)2 − 4·2·7 = 81 − 56 = 25
.x = [9 ± 5]/(4) ⇒ x = 14/4 = 7/2
or x = 4/4 = 1
.x = 1, 7/2
.x
km/h. If speed were 5 km/h more, journey would take 48 minutes less. Find x
.
360/x − 360/(x+5) = 48 min = 48/60 = 4/5 hours
.x(x+5)
: 360(x+5) − 360x = (4/5) x(x+5)
⇒ left = 360·5 = 1800
.1800 = (4/5) x(x+5)
⇒ multiply by 5: 9000 = 4x(x+5)
⇒ x2 + 5x − 2250 = 0
.D = 25 + 9000 = 9025 = 952
⇒ x = [−5 + 95]/2 = 90/2 = 45
(positive root).x = 45 km/h
.x2 − 10x + 25 = 0
(x−5)2 = 0
.x = 5
(repeated root).n
(odd). Then n(n+2)=255
.n2 + 2n − 255 = 0
. Discriminant D = 4 + 1020 = 1024 = 322
.n = [−2 ± 32]/2
⇒ positive root n = 15
.15, 17
.4x2 − 4√3 x + 3 = 0
D = (−4√3)2 − 4·4·3 = 48 − 48 = 0
.x = (4√3)/(2·4) = √3/2
.x = √3 / 2
(double root).ax2 + bx + c = 0
are equal, prove b2 = 4ac
.
D = b2 − 4ac = 0
by definition.b2 = 4ac
. (This is exactly the condition for equal roots.)b2 = 4ac
(proved).⌛Why Choose FUZY MATH ACADEMY for Quadratic Equations?
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AI-powered LMS with instant quizzes
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24/7 Chatbot for doubt solving
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Experienced faculty with shortcuts & tricks
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Affordable fees compared to offline coaching
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Progress tracking and personalized dashboard
💥Conclusion
Quadratic Equations are not just an academic topic but a life skill that develops reasoning and problem-solving ability. With proper guidance and regular practice, this chapter can fetch full marks in Class 10 board exams.
At FUZY MATH ACADEMY, we simplify learning with technology-driven teaching, round-the-clock support, and affordable plans. Whether you’re in Class 5 building foundations or in Class 12 aiming for competitive exams, our platform ensures you always stay ahead.
📞 Contact: 6264302661
Quadratic Equations – Important Questions with Solutions
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