Math modeling problem

[Jeri]

Hello. I’m trying to figure out how they got an answer for the problem
f(x)=3/2x-7
I understand the slope and Y intercept
Not sure how they got the answer (1,-11/2) for the second plot point. And how to plot it on a graph.

 

[Otis]

trying to figure out how they got an answer for the problem … (1,-11/2) for the second plot point

Hello Jeri. What problem were they working on?

Was the function definition f(x) = (3/2)x-7 given, and the problem was to graph the line by plotting the y-intercept and one other point?

The symbol f(x) is a variable. It represents the variable y.

The symbol f(1) represents the value of y when x=1.

f(1) = -11/2

In other words, when x=1 then y=-11/2

We determine the value of f(1) by substituting x=1 in the given function.

f(x) = (3/2)x - 7

f(1) = (3/2)(1) - 7

Do you know how to subtract 7 from 3/2?

I understand the slope and Y intercept … Not sure how … to plot it on a graph

Are you asking how to plot (x,y) points or are you asking how to plot the line?

The web page at the link below explains the xy-coordinate system and shows how to plot points.

Cartesian Coordinates

To graph the given function, we simply plot two points and use a straightedge to draw a line through the two points. As you already understand the y-intercept, you could use that point and the point (1,-11/2). Use graph paper!

 

[Jeri]

Got it. Thanks!