standard_description: Use similar triangles to explain why the slope m is the same between any two distinct points on a non-vertical line in the coordinate plane; derive the equation y = mx for a line through the origin and the equation y = mx + b for a line intercepting the vertical axis at b.
problem_activity: Problem 1
Tickets to a concert are available for early access on a special website. The website charges a fixed fee for early access to the tickets, and the tickets to the concert all cost the same amount with no additional tax. A friend of yours purchases 4 tickets on the website for a total of $162. Another friend purchases 7 tickets on the website for $270.
What function represents the total cost,
$$y$$
, for the purchase of
$$x$$
tickets on the website?
Problem 2
Write an equation in slope-intercept form for the line that passes through the points
$${(-2, -3)}$$
and
$${(1, 12)}$$
.


aligns: yes