Question

Liam is reading a 254-page book for school. He can read 40 pages in one hour. The equation for the number of pages he has left to read is y=254-40x, where x is the number of hours he reads.

a. State the slope and the y-intercept of the graph of the equation.
b. Graph the equation.
c. Interpret what the slope and the y-intercept represent.

Answer 1

So y=mx+b where m=the slope and b the y intercept is the equation you need to think about..
Now look at the equ. you have, y=254-40x, notice a similarity???
a.slope (m)=-40
y-intercept (b)= 254
b. To graph this, put a dot at (0,254) --this is the y-intercept remember, so thats where we are marking the y-axis at 254, then go down(b/c it's neg.) 40 over 1 (this is your slope remember, -40/1 or -40 over 1 ---which would =-40) and place another dot, connect the dots a voila! You've graphed it!!
c. So lets think, the y-intercept (254) is the starting point, when we've read zero hours we have 254 pages left. So the slope (-40) is the amount that we can read per hour, for every hour we read, we subtract 40 pages.