SOLUTION: find the rate of change and make a graph for: -$7.50 weekly for 12 weeks with a balance of $432.50 I thought it was using formula Y=mx+b but I am not sure. Thanks, Frank

Algebra ->  Linear-equations -> SOLUTION: find the rate of change and make a graph for: -$7.50 weekly for 12 weeks with a balance of $432.50 I thought it was using formula Y=mx+b but I am not sure. Thanks, Frank       Log On


   

Question 121564: find the rate of change and make a graph for: -$7.50 weekly for 12 weeks with a balance of $432.50 I thought it was using formula Y=mx+b but I am not sure.
Thanks,
Frank
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
the line formula Y=mX+b CAN BE USED TO GRAPH THIS PROBLEM.
FIRST WE NEED 2 POINTS.
THE END POINT IS (12,432.50)
THE BEGINNING POINT IS(0,432.50+12*7.50)=(0,522.5)
NOW WE NEED A SLOPE (m) & A Y INTERCEPT(b)
SLOPE=(522.5-432.5)/(0-12)=90/-12=-7.5
USING ONE WET OF X,Y VALUES & THE SLOPE WE NOW SOLVE FOR (b)
522.5=-7.5*0+b
b=522.5
THUS THE LINE EQUATION IS:
Y=-7.5X+522.5
+graph%28+500%2C+500%2C+-6%2C+80%2C+-10%2C+550%2C+y+=+-7.5x+%2B522.5%29+ (graph 500x500 pixels, x from -6 to 80, y from -10 to 550, y = -7.5x +522.5).