This subsection is not completed yet, but in the meantime here are some practice questions.

Remember:

Slope, which is usually given the letter $m$, is a measure of the steepness of a line. It is the number of units up or down for every unit across, and can be calculated by dividing the rise by the run.
A line connecting two points $(x_1,y_1)$ and $(x_2,y_2)$ will have a rise of $\Delta y = y_2 - y_1$ and a run of $\Delta x = x_2 - x_1$, with a slope of: \[m = \frac{\Delta y}{\Delta x}\]

Remember:

The steeper the line, the bigger the slope, $m$. A slope of $1$ is on a $45^\circ$ angle. A slope of $0$ will be horizontal. If the line is sloping downwards then either $\Delta y$ or $\Delta x$ will be negative, and so will the slope, $m$.

Remember:

To find the slope of a line given its equation, rewrite it in the form $y=mx + c$. For example,
\begin{align*}
y &= 2 + x\\
&= 1x + 2\\
m &= 1
\end{align*}
\begin{align*}
y &= 5 - \frac{x}{2}\\
&= -\frac{1}{2} x + 5\\
m &= -\frac{1}{2}
\end{align*}
\begin{align*}
2x + y + 3 &= 0\\
y &= -2x - 3\\
m &= -2
\end{align*}

Remember:

If a line with slope $m_1$ is perpendicular to another line with slope $m_2$ then \[m_1 m_2 = -1\]

Remember:

To find the y-intercept of a straight line (which is the $c$ in $y = mx + c$), knowing its slope, $m$, and a point on the line, $(x_1,y_1)$, there are a couple methods. You can say:
\[y-y_1 = m(x-x_1)\]
and then solve for $y$ to get it into the form $y = mx + c$. Or you could sub $(x_1,y_1)$ into the equation $y=mx+c$ to get:
\[y_1 = mx_1 + c\]
and then solve for $c$. In either case, $c = y_1 - mx_1$ will be the conclusion.