Use the quadratic formula to solve the quadratic equation 10x2+5x=5x−8 . Express its solutions in the form a±bi .(1 point)

1 answer

To solve the quadratic equation \(10x^2 + 5x = 5x - 8\), we first need to rearrange it into standard form \(ax^2 + bx + c = 0\).

Starting with the original equation:

\[ 10x^2 + 5x - 5x + 8 = 0 \]

This simplifies to:

\[ 10x^2 + 8 = 0 \]

Now we can rewrite the equation in standard form:

\[ 10x^2 + 0x + 8 = 0 \]

Here, \(a = 10\), \(b = 0\), and \(c = 8\).

Next, we will use the quadratic formula, which is given by:

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

Substituting the values of \(a\), \(b\), and \(c\) into the formula:

  1. Calculate \(b^2 - 4ac\):

\[ b^2 - 4ac = 0^2 - 4(10)(8) = 0 - 320 = -320 \]

  1. Now, substitute into the quadratic formula:

\[ x = \frac{-0 \pm \sqrt{-320}}{2(10)} \]

This simplifies to:

\[ x = \frac{\pm \sqrt{-320}}{20} \]

  1. Since \(\sqrt{-320} = \sqrt{320}i = \sqrt{64 \cdot 5}i = 8\sqrt{5}i\), we can express the equation as:

\[ x = \frac{\pm 8\sqrt{5}i}{20} \]

This simplifies to:

\[ x = \frac{\pm 2\sqrt{5}i}{5} \]

Thus, we can express the solutions as:

\[ x = 0 \pm \frac{2\sqrt{5}}{5} i \]

The final solutions in the form \(a \pm bi\) are:

\[ 0 \pm \frac{2\sqrt{5}}{5} i \]