The value of y varies directly with x, when y = 4, and x = 9. What is the equation for the relationship?

y  =  x

Step-by-step explanation:

Given parameters:

  y  = 4

   x  = 9

y varies directly as x ;

  Mathematically ;

            y ∝ x

So;

            y  = kx

k is the constant of proportionality;

  find k;

             k  =  

             k  =  

So,

  Equation of the relationship is;

            y  =  x

guess at question:

a vertical line intersects the graph of g(x,y) = 0 at two points. what conclusion follows about the function f(x) implicitly defined by g(x,f(x)) = 0?

the domain of f(x) cannot include the x coordinate of any such vertical line.

informally, f(x) is not a function, and

g(x,y)=0 cannot be solved for y uniquely.

the relation r = {(x,y) such that g(x,y) = 0} is a function if

for all (a,b) ∊ r and (c,d) ∊ r, a=c implies b=d.

step-by-step explanation: