Will someone please help me figure out how to answer this question?
At Generic High School, in the year 2001, there were 20 students per every computer. In 2008, there were 4.5 students per computer.

During which year were there 10 students per computer?

Question

Will someone please help me figure out how to answer this question?
At Generic High School, in the year 2001, there were 20 students per every computer. In 2008, there were 4.5 students per computer.

During which year were there 10 students per computer?

anonymous · Answer

is this relation supposed to be linear?

anonymous · Answer

if so, in 8 years it went from 20 to 4.5 making your slope $\frac{4.5-20}{8}$

abbycross167 · Answer

Umm I really don't know...  I think so

abbycross167 · Answer

@satellite73

anonymous · Answer

$$\frac{4.5-20}{7}=-\frac{31}{14}$$

anonymous · Answer

your linear model is $$y=-\frac{31}{14}+20$$ set that equal to $10$ and solve for $x$

anonymous · Answer

that is wrong sorry 
it is$$y=-\frac{31}{14}x+20$$

abbycross167 · Answer

17  11/14?

abbycross167 · Answer

@jim_thompson5910  could you please try to help me answer the question?

jim_thompson5910 · Answer

ok one moment

abbycross167 · Answer

ok thank you

jim_thompson5910 · Answer

use the equation @satellite73 wrote out

plug in y = 10 and solve for x

$$\Large y = -\frac{31}{14}x + 20$$

$$\Large 10 = -\frac{31}{14}x + 20$$

$$\Large 10-20 = -\frac{31}{14}x + 20-20$$

$$\Large -10 = -\frac{31}{14}x$$

do you see how to finish?

abbycross167 · Answer

umm maybe... would I divide -31/14 by -10?

jim_thompson5910 · Answer

or multiply both sides by the reciprocal of the fraction

abbycross167 · Answer

ok would you mind showing me so I know i got it right?

jim_thompson5910 · Answer

ok so we have this equation
|dw:1449637397806:dw|

jim_thompson5910 · Answer

multiply both sides by -14/31

this is the reciprocal of -31/14

|dw:1449637448465:dw|