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March 31st, 2014, 07:44 PM  #1 
Newbie Joined: Mar 2014 Posts: 12 Thanks: 0  Is it possible to form the equations without looking at the answer choices?
I wanted to know if it's possible to form the equations, without plugging in values. Question is attached below.

April 1st, 2014, 01:52 AM  #2 
Senior Member Joined: Dec 2013 From: Russia Posts: 327 Thanks: 108 
A linear function (whose graph is) passing through points $\displaystyle (x_1,y_1)$ and $\displaystyle (x_2,y_2)$ has equation $\displaystyle \frac{yy_1}{xx_1}=\frac{y_2y_1}{x_2x_1}$. In this case, $\displaystyle x_1=7$, $\displaystyle x_2=9$, $\displaystyle y_1=30$ (thousand) and $\displaystyle y_2=22$. So, the equaton is $\displaystyle \frac{y30}{x7}=\frac{8}{2}=4$ i.e., $\displaystyle y30=4(7x)=284x$ $\displaystyle y=584x$. 
April 1st, 2014, 11:48 AM  #3 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 14,597 Thanks: 1039  Hockey
Evgeny, are you related to Sergei? Legends of Hockey  NHL Player Search  Player  Sergei Makarov 
April 1st, 2014, 11:50 AM  #4 
Senior Member Joined: Dec 2013 From: Russia Posts: 327 Thanks: 108 
Haha, no. Makarov is not the most popular last name in Russia, but it is not unusual, either.


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