Factor to solve the equation 4x2+12x+5=−4.(1 point)

Responses

x=112
1 Start Fraction 1 over 2 End Fraction

x=23
Start Fraction 2 over 3 End Fraction

x=−112
negative 1 Start Fraction 1 over 2 End Fraction

x=−23

1 answer

To solve the equation \( 4x^2 + 12x + 5 = -4 \), we first move the -4 to the left side:

\[ 4x^2 + 12x + 5 + 4 = 0 \]

This simplifies to:

\[ 4x^2 + 12x + 9 = 0 \]

Next, we can factor the quadratic equation. We look for two numbers that multiply to \( 4 \cdot 9 = 36 \) and add up to \( 12 \). The numbers 6 and 6 fit this requirement.

Thus, we can write the equation as:

\[ 4x^2 + 6x + 6x + 9 = 0 \]

Now, we group the terms:

\[ (4x^2 + 6x) + (6x + 9) = 0 \]

Factoring by grouping gives:

\[ 2x(2x + 3) + 3(2x + 3) = 0 \]

Now factor out the common term \( (2x + 3) \):

\[ (2x + 3)(2x + 3) = 0 \] or simplifying further, \[ (2x + 3)^2 = 0 \]

Now we can set the factor equal to zero:

\[ 2x + 3 = 0 \]

Solving for \( x \):

\[ 2x = -3 \] \[ x = -\frac{3}{2} \]

Thus, the solution to the equation is:

\[ x = -\frac{3}{2} \]

In terms of your options, that is equivalent to:

\[ x = -2 \frac{1}{2} \quad \text{or} \quad x = -\frac{3}{2} \]

So the answer is \( x = -2 \frac{1}{2} \) or negative \( \frac{3}{2} \).