Solve the quadratic equation 84x^2+16x=0 by factoring out the GCF.(1 point) Responses The solutions are x=−421 and x=0 . The solutions are x equals negative Start Fraction 4 over 21 End Fraction and x equals 0 . The solutions are x=0 and x=421 . The solutions are x equals 0 and x equals Start Fraction 4 over 21 End Fraction . The solutions are x=0 and x=4 . The solutions are x equals 0 and x equals 4 . The solutions are x=−4 and x=−421 .

1 answer

To solve the quadratic equation \( 84x^2 + 16x = 0 \) by factoring out the greatest common factor (GCF), we first identify the GCF of the terms:

  1. \( 84x^2 \)
  2. \( 16x \)

The GCF of \( 84 \) and \( 16 \) is \( 4 \), and both terms also contain \( x \). Thus, the GCF is \( 4x \).

Now, we can factor out \( 4x \) from the equation:

\[ 84x^2 + 16x = 4x(21x + 4) = 0 \]

Next, we set each factor equal to zero:

  1. From \( 4x = 0 \): \[ x = 0 \]

  2. From \( 21x + 4 = 0 \): \[ 21x = -4 \quad \Rightarrow \quad x = -\frac{4}{21} \]

Thus, the solutions to the equation \( 84x^2 + 16x = 0 \) are:

\[ x = 0 \quad \text{and} \quad x = -\frac{4}{21} \]

The correct response is:

The solutions are \( x = 0 \) and \( x = -\frac{4}{21} \).