Solve the quadratic equation 84x2+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=−4 and x=−421 . The solutions are x equals negative 4 and x equals negative 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=0 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 two terms:

The GCF of \(84x^2\) and \(16x\) is \(4x\).

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

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

Now we set each factor equal to zero:

  1. \(4x = 0\)
    This gives us:
    \[ x = 0 \]

  2. \(21x + 4 = 0\)
    Solving for \(x\):
    \[ 21x = -4
    \] \[ x = -\frac{4}{21} \]

So the solutions to the equation \(84x^2 + 16x = 0\) are: \[ x = 0 \quad \text{and} \quad x = -\frac{4}{21} \]

Thus, the correct option is:
The solutions are \(x = -\frac{4}{21}\) and \(x = 0\).