Solve (x-1/2)(x+6.5): Finding Positive Domain of Quadratic Function

To find when the function $y = \left(x - \frac{1}{2}\right)\left(x + 6\frac{1}{2}\right)$ is positive, we proceed as follows:

First, identify the roots of the expression by solving $x - \frac{1}{2} = 0$ and $x + 6\frac{1}{2} = 0$. These calculations give us the roots $x = \frac{1}{2}$ and $x = -6\frac{1}{2}$, or $x = -\frac{13}{2}$.

Next, determine the sign of the product $(x - \frac{1}{2})(x + \frac{13}{2})$ over the intervals defined by these roots:

• Interval 1: $x < -\frac{13}{2}$. In this region, both $x - \frac{1}{2}$ and $x + \frac{13}{2}$ are negative, so their product is positive.
• Interval 2: $-\frac{13}{2} < x < \frac{1}{2}$. In this region, $x + \frac{13}{2}$ is positive and $x - \frac{1}{2}$ is negative, so their product is negative.
• Interval 3: $x > \frac{1}{2}$. In this region, both $x - \frac{1}{2}$ and $x + \frac{13}{2}$ are positive, so their product is positive.

Therefore, the function is positive for $x < -6\frac{1}{2}$ and $x > \frac{1}{2}$.

Thus, the solution is:
$x > \frac{1}{2}$ or $x < -6\frac{1}{2}$