Question

. Two trains leave a train station traveling different directions. The first train travels 12 miles west, then 6 miles north. The second train travels 20 miles east, then 35 miles north. a. The train station is the origin. What is the coordinate of each train? b. Using the train station and the stop point of the first train, what is the slope of the line? Is it horizontal, vertical or neither? Write the equation of the line in slope-intercept form and standard form. c. The city wants to build a second train station 2 miles directly north of the first train station. They are going to build a train track from the second train station that is parallel to the path the first train would've traveled if it had taken a direct route to its stopping point. What would be the equation of the line in slope intercept form of the new track?

Answer 1

Answer:

a. The coordinates of the first train are (-12,6).  The coordinates of the second train are (20,35).

b. The slope of the line for the first train is $-\frac{1}{2}$.  The slope is neither horizontal or vertical.  It slopes diagonally downward from left to write since the slope is negative.  In slope-interdept form, it is written as $y=-\frac{1}{2} x$.  In standard form, it is written as $x+2y=0$.   The slope of the line for the second train is $\frac{7}{4}$.  The slope is neither vertical or horizontal.  It slopes diagonally upward from left to right since the slope is positive.  In slope-intercept form, it is written as $y=\frac{7}{4}x$.  In standard form, it is written as $-7x+4y=0$.

c. The equarion of a line in slope-intercept form of the new track would be $y=-\frac{1}{2} x+2$.

Step-by-step explanation:

a.  The way to find the coordinates is either to picture a coordinate grid in your head or to have one out in front of you for a visual.  The first train travels 12 miles west, or 12 units to the left (-12), and 6 miles north, or 6 units up (6).  On a coordinate plane, that would be marked as (-12,6).  The second train travels 20 miles east, or 20 units to the right (20), and 35 miles north, or 35 units up (35).  On a coordinate plane that would be marked as (20,35).  This means that the coordinates of the first train would be (-12,6), and the coordinates of there second train would be (20,35).

b. The way to find slope is to find $\frac{delta "x"}{delta "y"}$.  "Delta" means "the change in".  The equation would be $m=\frac{y_{2}-y_{1} }{x_{2}-x_{1} }$.  So, let's find the slope of the first train's travel path.  We'll use the origin, (0,0), and the stopping point, (-12,6), as our coordinates to find the slope.  $\frac{0-6}{0-(-12)}=\frac{0-6}{0+12}=\frac{-6}{12}=\frac{-1}{2}=-\frac{1}{2}$.  That makes the slope of the first train's travel path to be (-1/2).  Now, let's find the slope of the second train's travel path.  We'll use the origin, (0,0), and the stopping point, (20,35), as our coordinates to find the slope.  $\frac{0-35}{0-20}=\frac{-35}{-20}=\frac{35}{20}=\frac{7}{4}$.  That makes the slope of the second train's travel path to be (7/4).  They want to know the equation of the travel path line in slope-intercept form and in standard form, and what the line looks like.  To start off, any vertical line would be undefined, and that would be if the slope was a fraction with a denominator of zero, which doesn't occur for either train path.  A horizontal line  would be if the slope was zero itself and the trains were not moving, but the trains are moving, so that's not possible either.  The way to determine theway a slope is diagonally is to look at whether the slope is positive or negative.  The first train's path slopes negatively, so it moves diagonally downward from left to right, or diagonally upward from right to left (both the same thing).  The second train's path slopes positively, so it moves diagonally upward from left to right, or diagonally downward from right to left.  Finally, the equations for this part of the question.  For both trains, the origin is the y-intercept, so the y-intercept does not have to be written in the slope-intercept equation.  The slope-intercept form of an equation of a line is $y=mx+b$ where "m" is the slope and "b" is the y-intercept.  The "b" value is 0, so that will not be written.  The slope for the first train is (-1/2), so the slope-intercept form of the first train's travel path is y=(-1/2)x.  The slope of the second train is (7/4), so the slope-intercept form for this train's path is y=(7/4)x.  As for standard form, subtract the "mx" value from both sides, and set the equation equal to 0. Also, get rid of any fractions. So, for the first train, standard form would be x+2y=0.  And for the second train, standard form would be -7x+4y=0.

c.  Parallel means having the same slope but a different y-intercept.  The second train station would be placed two miles north, or two units up, from the first train station.  The first train station is at (0,0), so the second train station would be placed at (0,2).  That makes 2 the y-intercept for if the first train had taken the second train station's travel route.  The slope for the intitial route was (-1/2), so that will stay the same.  Therefore, the equation of thr route taken if the first train had come out of the second train station, if it was already built, would be y=(-1/2x)+2.