Solution assignment 07 Linear functions and graphs

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Assignment 7

The line $l$ goes through the points $A(2,1)$ and $B(0,3)$ and intersects the line:

$m: y=2x$

in point $S$ .
Calculate the coordinates of $S$ .

Solution

The equation of the line $l$ is not yet known and has to be determined. We can calculate the slope $r$ of $l$ with:

$r=\displaystyle\frac{y_B-y_A}{x_B-x_A}=\displaystyle\frac{3-1}{0-2}=-1$

Now we have the slope of $l$ we can calculate the equation and therefore we have to choose one of the points $A$ and $B$ . We choose the point $B$ , so:

$y-y_B=r(x-x_B)$
$y-3=-1(x-0)$
$y=-x+3$

We find the $x$ -coordinate of the intersection point $S$ by solving:

$2x=-x+3$
$x=1$

and thus we have:

$y=2$

The intersection point $S$ has the coordinates $(1,2)$ .
Check this in the figure.

Return to Assignments Linear functions and graphs.

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Solution assignment 07 Linear functions and graphs

Assignment 7

Solution

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