Respuesta :

Answer:

5x=6

x=6/5

y=-8/5

Step-by-step explanation:

Answer:  2x-y=4 if you're looking for y then y=4/-1 or -4.0000 and x= 4/2 or 2

3x+y=21: if you're looking for y then y=21/1 in decimal form 21.00000

x= 21/3 or 7

slope=6.000/2.000 or -3.000

Step-by-step explanation:  3x+y-21  = 0

we have here an equation of a straight line. Such an equation is usually written y=mx+b ("y=mx+c".

"y=mx+b" is the formula of a straight line drawn on Cartesian coordinate system in which "y" is the vertical axis and "x" the horizontal axis.

In this formula :

y tells us how far up the line goes

x tells us how far along

m is the Slope or Gradient i.e. how steep the line is

b is the Y-intercept i.e. where the line crosses the Y axis

The X and Y intercepts and the Slope are called the line properties. We shall now graph the line  3x+y-21  = 0 and calculate its properties

Graph of a Straight Line :

 

 

Calculate the Y-Intercept :

Notice that when x = 0 the value of y is 21/1 so this line "cuts" the y axis at y=21.00000

 y-intercept = 21/1  = 21.00000  

Calculate the X-Intercept :

When y = 0 the value of x is 7/1 Our line therefore "cuts" the x axis at x= 7.00000

 x-intercept = 21/3  =  7  

Calculate the Slope :

Slope is defined as the change in y divided by the change in x. We note that for x=0, the value of y is 21.000 and for x=2.000, the value of y is 15.000. So, for a change of 2.000 in x (The change in x is sometimes referred to as "RUN") we get a change of 15.000 - 21.000 = -6.000 in y. (The change in y is sometimes referred to as "RISE" and the Slope is m = RISE / RUN)

   Slope     = -6.000/2.000 = -3.000  

 Slope = -6.000/2.000 = -3.000

 x-intercept = 21/3 = 7

 y-intercept = 21/1 = 21.00000