In Exercises pointslopegivenlinefirst - pointslopegivenlinelast, find both the point-slope form and the slope-intercept form of the line with the given slope which passes through the given point.
\(m = 3, \;\; P(3, -1)\)

The point slope form is ...

\(y+1=3(x-3)\)

The slope-intercept form is

\(y = \answer {3}x + \answer {-10}\)

\(m = -2, \;\; P(-5, 8)\)

The point slope form is ...

\(y-8 = -2(x+5)\)

The slope-intercept form is

\(y = \answer {-2}x + \answer {-2}\)

\(m = -1, \;\; P(-7, -1)\)

The point slope form is ...

\(y + 1 = -(x+7)\)

The slope-intercept form is

\(y = \answer {-1}x + \answer {-8}\)

\(m = \frac {2}{3}, \;\; P(-2, 1)\)

The point slope form is ...

\(y - 1 = \frac {2}{3} (x+2)\)

The slope-intercept form is

\(y = \answer {\frac {2}{3}} x + \answer {\frac {7}{3}}\)

\(m = -\frac {1}{5}, \;\; P(10, 4)\)

The point slope form is ...

\(y - 4 = -\frac {1}{5} (x-10)\)

The slope-intercept form is

\(y = \answer {-\frac {1}{5}}x + \answer {6}\)

\(m = \frac {1}{7}, \;\; P(-1, 4)\)

The point slope form is ...

\(y - 4 = \frac {1}{7}(x + 1)\)

The slope-intercept form is

\(y = \answer {\frac {1}{7}}x + \answer {\frac {29}{7}}\)

\(m = 0, \;\; P(3, 117)\)

The point slope form is ...

\(y - 117 = 0\)

The slope-intercept form is

\(y = \answer {117}\)

\(m = -\sqrt {2}, \;\; P(0, -3)\)

The point slope form is ...

\(y + 3 = -\sqrt {2}(x - 0)\)

The slope-intercept form is

\(y = \answer {-\sqrt {2}}x + \answer {-3}\)

\(m = -5, \;\; P(\sqrt {3}, 2\sqrt {3})\)

The point slope form is ...

\(y - 2\sqrt {3} = -5(x - \sqrt {3})\)

The slope-intercept form is

\(y = \answer {-5}x + \answer {7\sqrt {3}}\)

\(m = 678, \;\; P(-1, -12)\)

The point slope form is ...

\(y + 12 = 678(x + 1)\)

The slope-intercept form is

\(y = \answer {678}x + \answer {666}\)

In Exercises twopointsgivenlinefirst - twopointsgivenlinelast, find the slope-intercept form of the line which passes through the given points.
\(P(0, 0), \; Q(-3, 5)\)

\(y = \answer {-\frac {5}{3}}x\)

\(P(-1, -2), \; Q(3, -2)\)

\(y = \answer {-2}\)

\(P(5, 0), \; Q(0, -8)\)

\(y = \answer {\frac {8}{5}}x + \answer {-8}\)

\(P(3, -5), \; Q(7, 4)\)

\(y = \answer {\frac {9}{4}}x + \answer {-\frac {47}{4}}\)

\(P(-1,5), \; Q(7, 5)\)

\(y = \answer {5}\)

\(P(4, -8), \; Q(5, -8)\)

\(y = \answer {-8}\)

\(P\left (\frac {1}{2}, \frac {3}{4} \right ), \; Q\left (\frac {5}{2}, -\frac {7}{4} \right )\)

\(y = \answer {-\frac {5}{4}} x + \answer {\frac {11}{8}}\)

\(P\left (\frac {2}{3}, \frac {7}{2} \right ), \; Q\left (-\frac {1}{3}, \frac {3}{2} \right )\)

\(y = \answer {2}x + \answer {\frac {13}{6}}\)

\(P\left (\sqrt {2}, -\sqrt {2} \right ), \; Q\left (-\sqrt {2}, \sqrt {2} \right )\)

\(y = \answer {-1}x\)

\(P\left (-\sqrt {3}, -1 \right ), \; Q\left (\sqrt {3}, 1 \right )\)

\(y = \answer {\frac {\sqrt {3}}{3}} x\)

In Exercises graphlineexerfirst - graphlineexerlast, graph the line. Find the slope, \(y\)-intercept and \(x\)-intercept, if any exist.
\(y = 2x - 1\)

Slope \(=2\), y-intercept is \((0,-1)\), x-intercept is \((\frac {1}{2},0)\)

\(y = 3 - x\)

Slope \(=-1\), y-intercept is \((0,3)\), x-intercept is \((3,0)\)

\(y = 3\)

Slope \(=0\), y-intercept is \((0,3)\), no x-intercept

\(y = 0\)

Slope \(=0\), y-intercept is \((0,0)\), x-intercept is \((0,0)\)

\(y = \frac {2}{3} x + \frac {1}{3}\)

Slope \(=\frac {2}{3}\), y-intercept is \((0,\frac {1}{3})\), x-intercept is \((-\frac {1}{2},0)\)

\(y = \frac {1-x}{2}\)

Slope \(=\frac {-1}{2}\), y-intercept is \(\frac {1}{2}\), x-intercept is \((1,0)\)

Graph \(3v + 2w = 6\) on both the \(vw\)- and \(wv\)-axes. What characteristics to both graphs share? What’s different?

\(w = -\frac {3}{2} v + 3\) slope: \(m = -\frac {3}{2}\) \(w\)-intercept: \(\left (0, 3\right )\) \(v\)-intercept: \(\left (2, 0\right )\)

\(V = -\frac {2}{3} W + 2\) slope: \(m = -\frac {2}{3}\) \(V\)-intercept: \(\left (0,2 \right )\) \(W\)-intercept: \(\left (3,0\right )\)

Find all of the points on the line \(y=2x+1\) which are \(4\) units from the point \((-1,3)\).

\((-1,-1)\) and \(\left (\frac {11}{5}, \frac {27}{5}\right )\)
In Exercises parallelfirst - parallellast, you are given a line and a point which is not on that line. Find the line parallel to the given line which passes through the given point.
\(y = 3x + 2, \; P(0, 0)\)

\(y = \answer {3}x\)

\(y = -6x + 5, \; P(3, 2)\)

\(y = \answer {-6}x + \answer {20}\)

\(y = \frac {2}{3} x - 7, \; P(6, 0)\)

\(y = \answer {\frac {2}{3}} x + \answer {-4}\)

\(y = \frac {4-x}{3}, \; P(1, -1)\)

\(y = \answer {-\frac {1}{3}} x + \answer {-\frac {2}{3}}\)

\(y = 6, \; P(3, -2)\)

\(y= \answer {-2}\)
\(x=1, \; P(-5,0)\)

\(x= \answer {-5}\)

In Exercises perpendlinefirst - perpendlinelast, you are given a line and a point which is not on that line. Find the line perpendicular to the given line which passes through the given point.
\(y = \frac {1}{3}x + 2, \; P(0, 0)\)

\(y = \answer {-3}x\)

\(y = -6x + 5, \; P(3, 2)\)

\(y = \answer {\frac {1}{6}}x + \answer {\frac {3}{2}}\)

\(y = \frac {2}{3} x - 7, \; P(6, 0)\)

\(y = \answer {-\frac {3}{2}} x + \answer {9}\)

\(y = \frac {4-x}{3}, \; P(1, -1)\)

\(y = \answer {3}x + \answer {-4}\)

\(y = 6, \; P(3, -2)\)

\(x=\answer {3}\)

\(x=1, \; P(-5,0)\)

\(y=\answer {0}\)

We shall now prove that \(y = m_1x + b_1\) is perpendicular to \(y = m_2x + b_2\) if and only if \(m_1 \cdot m_2 = -1\). To make our lives easier we shall assume that \(m_1 > 0\) and \(m_2 < 0\). We can also “move” the lines so that their point of intersection is the origin without messing things up, so we’ll assume \(b_1 = b_2 = 0.\) (Take a moment with your classmates to discuss why this is okay.) Graphing the lines and plotting the points \(O(0, 0)\;\), \(P(1, m_1)\;\) and \(Q(1, m_2)\) gives us the following set up.

[Picture]

The line \(y = m_1x\) will be perpendicular to the line \(y = m_2x\) if and only if \(\bigtriangleup OPQ\) is a right triangle. Let \(d_1\) be the distance from \(O\) to \(P\), let \(d_2\) be the distance from \(O\) to \(Q\) and let \(d_3\) be the distance from \(P\) to \(Q\). Use the Pythagorean Theorem to show that \(\bigtriangleup OPQ\) is a right triangle if and only if \(m_1 \cdot m_2 = -1\) by showing \(d_1^{2} + d_2^{2} = d_3^2\) if and only if \(m_1 \cdot m_2 = -1\).