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Question

What is the square root of the following?
$(x^2 - 14x + 49)(x^2 + 6x + 9)$

This question was previously asked in
RRB NTPC 2019 CBT 1 Question Paper (8-Mar-2021) (Shift 2)
The correct answer is
$(x - 7)(x + 3)$

Factoring the Algebraic Expression

The expression provided is: $(x^2 - 14x + 49)(x^2 + 6x + 9)$

To find its square root, we first factor each quadratic part.

  • The first quadratic, $x^2 - 14x + 49$, is a perfect square trinomial. It factors as $(x - 7)^2$.
  • The second quadratic, $x^2 + 6x + 9$, is also a perfect square trinomial. It factors as $(x + 3)^2$.

Substituting these factors back, the expression becomes:

$(x - 7)^2 (x + 3)^2$

Calculating the Square Root

Now, we calculate the square root of this factored expression:

$\sqrt{(x - 7)^2 (x + 3)^2}$

Using the property $\sqrt{a^2 b^2} = \sqrt{a^2}\sqrt{b^2} = |a||b|$, we get:

$|x - 7| \times |x + 3|$

In algebraic contexts like this multiple-choice question, the principal square root is typically considered, simplifying to:

$(x - 7)(x + 3)$

This result matches Option B.

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Similar Questions

  1. When $x^{4} - px^{3} + 2x^{2} - 5x + 8$ is divided by $x - 1$, the remainder is $2p$. The value of $p$ is:
  2. When $x^4 + x^3 - x^2 + x + 1$ is divided by $x - 3$, the remainder is:
  3. Simplify: $x(2x - 3) + 2(x^2 - 4) + 16$
  4. If $x^2 - 1$ is a factor of $ax^4 + bx^3 + cx^2 + dx + e$, then which of the following is a possible relation between the coefficients of powers of x
  5. If $(x + 1)$ and $(x + 2)$ are factors of $ax^3 + 3x^2 + bx$ then the values of $a$ and $b$ are:

  6. What is the remainder of function $4a^3 - 12a^2 + 14a - 3$ when it is divided by \(\frac{a-1}{2}\)?

  7. If polynomials $4x^3 + ax^2 - 3x + 1$ and $x^4 + x^3 - x^2 + 6$ leave the same remainder when each is divided by $(x+1)$, then the value of a is:
  8. Solve the following. 

    Subtract $\frac{9}{2} + \frac{x}{2} + \frac{3}{5}x^2 + \frac{7}{4}x^3$ from $\frac{7}{2} - \frac{x}{3} - \frac{1}{5}x^2$.

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Important Questions from Polynomials

  1. If (x + y) 3+ 8 (x - y) 3= (3x + Ay) (3x 2+ Bxy + Cy 2), then the value of A + B + C is:

  2. Given that x 8- 34x 4+ 1 = 0, x > 0. What is the value of (x 3+ x -3 )?

  3. If \(x - \frac 3 x = 6,\; x \ne 0,\)  then the value of  \(\frac {x^4 - \frac {27}{x^2}}{x^2 - 3x - 3}\)  is:

  4. If \(x\left(3 - \frac 2 x\right) = \frac 3 x,\)  then the value of  \(x^3 - \frac 1 {x^3}\)  is equal to:

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