y=7/9x-7 is? I need to plot on graph.

Question

I'm working on Graph of Linear Equations in two variables;  I selected (0, -7 for x)  & (1, ?  for y).  I'm having a difficult time finding what the other number is for y and this number to plot the points on the graph.

 

y=7/9x-7

 

Answer 1

Hi Marie;

y=7/9x-7

(0, -7 for x) & (1, ? for y)

(0,-7) is a coordinate for x and y, not "for x".

As per your first coordinate, (0,-7), this equation is...

y=(7/9x)-7

y=-7

The problem is that zero cannot be a denominator in the field of mathematics.  The domain of this equation, all values of x, is...

(-infinity,0)U(0,+infinity)

If the equation is...

y=7/(9x-7)

the domain would be...

(-infinity,7/9)(7/9,+infinity)

and such coordinate of x=0 is possible, but y=(7/-7)=-1.  The coordinate is (0,-1).

Answer 2

so when x = 0, y is 

y = 7/9 * 0 - 7 = -7

 

when x = -7, y is

y = 7/9*(-7) - 7 = something

 

why dont you choose when x = 9 it is a lot easier

 

when x = 9, y = 7/9*9 - 7 = 0

 

so the two points would be (0,-7) and (9,0)