SOLUTION: Our teacher never showed us how to work out a problem like this so I am confused. Can you please help me and explain how you got this answer so I know how to do it for my test.

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Our teacher never showed us how to work out a problem like this so I am confused. Can you please help me and explain how you got this answer so I know how to do it for my test.       Log On


   

Question 841052: Our teacher never showed us how to work out a problem like this so I am confused. Can you please help me and explain how you got this answer so I know how to do it for my test.
If 10 shirts cost $110 and 30 shirts cost $280, write a linear equation that gives the cost for n shirts.
Thank you!
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

write a linear equation (First find slope)

(30,280)

(10,110) +m+=+170%2F20+=+17%2F2+=+highlight%288.5%29

 y+=+8.5x+%2B+b   |Using slope Intercept Form

110 = 8.5(10) + b   |Using Ordered Pair (10,110) to solve for b

 25= b

AND

 y = 8.5 x+ 25   |  Where y is the cost of x shirts

CHECKING our answer***

8.5* 30 + 25 = 255 + 25 = $280

Wish You the Best in your Studies.