Use the quadratic formula to solve the equation.

15ysquaredplus 32yplus 16equals0
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Part 1
A.
four thirds
​, four fifths

B.
minusfour thirds
​, minusfour fifths

C.
four thirds
​, minusfour fifths
D.
minusfour fifteenths
​, minusone fourth

1 answer

To solve the quadratic equation \(15y^2 + 32y + 16 = 0\), we can use the quadratic formula, which is given by:

\[ y = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \]

In your equation, \(a = 15\), \(b = 32\), and \(c = 16\).

Now we need to calculate the discriminant (\(b^2 - 4ac\)):

\[ b^2 = 32^2 = 1024 \] \[ 4ac = 4 \cdot 15 \cdot 16 = 960 \]

So, the discriminant is:

\[ b^2 - 4ac = 1024 - 960 = 64 \]

Now that we have the discriminant, we can find \(y\):

\[ y = \frac{-32 \pm \sqrt{64}}{2 \cdot 15} \]

The square root of 64 is 8, so we have:

\[ y = \frac{-32 \pm 8}{30} \]

This gives us two solutions:

  1. \(y = \frac{-32 + 8}{30} = \frac{-24}{30} = -\frac{4}{5}\)
  2. \(y = \frac{-32 - 8}{30} = \frac{-40}{30} = -\frac{4}{3}\)

So the solutions are:

\[ y = -\frac{4}{3}, \quad y = -\frac{4}{5} \]

The correct answer is B. \( -\frac{4}{3}, -\frac{4}{5} \).