All Exams Test series for 1 year @ ₹349 only
Question

Solve for x in \(12x^2 + 45x = 0\)

This question was previously asked in
RRB ALP 2018 CBT 2 Fitter Question Paper (21-Jan-2019) (Shift 3)
The correct answer is
$x = 0, x = \frac{-15}{4}$

Solving the Quadratic Equation

The given equation is a quadratic equation:

\(12x^2 + 45x = 0\)

To solve for x, we can factor out the common term, which is x.

Factorization Step

Factor out x from the equation:

\(x(12x + 45) = 0\)

Applying the Zero Product Property

According to the zero product property, if the product of two factors is zero, then at least one of the factors must be zero.

This gives us two possible cases:

  • Case 1: The first factor is zero. \(x = 0\)
  • Case 2: The second factor is zero. \(12x + 45 = 0\)

Solving for x in Case 2

Solve the linear equation from Case 2:

  1. Subtract 45 from both sides: \(12x = -45\)
  2. Divide both sides by 12: \(x = \frac{-45}{12}\)
  3. Simplify the fraction by dividing the numerator and denominator by their greatest common divisor, which is 3: \(x = \frac{-45 \div 3}{12 \div 3} = \frac{-15}{4}\)

Final Solutions

The solutions for the equation \(12x^2 + 45x = 0\) are:

\(x = 0 \quad \text{and} \quad x = \frac{-15}{4}\)

Was this answer helpful?

Similar Questions

  1. Find the minimum value of 2x² – 5x – 3 and also find x.

  2. The difference between the roots of the equation \(x^2 - 6x - 16 = 0\) is:
  3. What is the quadratic equation whose roots are 5 and 2
  4. Find the quadratic equation with real coefficients which has (-5-i) as a root.
  5. The difference between the roots of the equation \(x^2 - 6x - 16 = 0\) is:
  6. A class of 30 students appeared in a test. The average score of 12 students is 80, and that of the rest is 75. What is the average score of the class?

  7. Find the value of x² + y², given that, x = 7 + √1, y = 7 - √1.


Important Questions from Quadratic equation

  1. Find the minimum value of 2x² – 5x – 3 and also find x.

  2. A quadratic equation $x^2 + 3x + k = 0$ has a discriminant equal to 9. What is the value of k?

  3. Reduce the equation $x^4 - 13x^2 + 36 = 0$ into a quadratic equation and find the roots of the reduced quadratic equation.
  4. If both roots of the quadratic equation, $x^2 + 3x + 2 = 0$, are also roots of another quadratic equation, $ax^2 + bx + c = 0$, then which of the following must be true?

  5. The nature of the roots of the quadratic equation $3x^{2} – 5x + 2 = 0$ is:
Need Expert Advice?
Upcoming Exams
RRB Technician
October 06, 2026
RRB JE
October 27, 2026
RRB ALP
November 03, 2026
Test Series
RRB ALP img
Railways
RRB ALP 2026 Mock Test series
1035 Tests 1 Tests Free
1083 Attempts
4.3(239)
English, Hindi

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App