Now i know we cant graph on here...but...could anyone explain how to do this to me??

Question

Solve the system by graphing
3x + y = 6
3x – y = 0

Answer 1

y = -3x + 6
y = 3x

when you graph the two - find the intersection and thats the answer to the question (1,3)

Answer 2

Do you know how to graph equations like this?
Substitute various values for x, and see what the y value must be.

e.g. for 3x + y = 6, put x = 0, and the equation becomes
3.(0) + y = 6
i.e. y = 6
So mark (0, 6) on the graph (i.e. on the y axis, 6 units up)

Put x = 1, and we get y = 3, so mark the point (1, 3) on the graph, and so on. In fact these two points are enough since graphs of equations like this are straight lines, but if you plot a couple more points (such as (2, 0), (3, -3)) it will confirm that you have the correct line besides helping draw it accurately. Draw the line through the points you have plotted.

Use the same method for 3x - y = 0. You might get the points (0, 0), (-2, -6) and (2, 6). Draw the line through these points.

The two lines cross at the point (1, 3), and so the solution of the system is x = 1, y = 3

Answer 3

Solve the 1st equation for y if x = 0.
Plot this point (0,y) on your graph paper.
Solve the 1st equation fo x if y = 0.
Plot this point (x,0).
To check, solve the equation a third time using any arbitrary value of x or y (not both, of course) that will fit on your graph paper.
Plot this point (x,y).
Using a straight-edge, see if these 3 points are in a straight line.
If so, draw a line passing through the 3 points.
If not, one or more of the points is wrong. correct the error(s) and draw the line .

Repeat this process for the 2nd equation.

Hopefully, these lines will cross somewhere. (In this case, I assure you they will.)

The solution to the system is the point where the lines cross.

Read this point off the graph.

Answer 4

first, rearrange both equations to slope-intercept form (y=mx+b)

3x+y=6 ________ 3x-y = 0
y=6-3x _______ -y = -3x

y=-3x+6 _______ y = 3x +0

m= -3/1 _________ m =3/1
b=6 ___________ b = 0

next, draw each line. Start from the y-intercept (b; 6 in the left equ. 0 in the right one). slope (m) = rise over run, so the line on the left goes down 3, right 1. Count down 3, right 1 from 6.
You now have two points (0,6) and (1,3) connect these and finish the line. Do the same for the right equation, except up 3, right one, starting from 0. (your points are (0,0) and (1,3). The solution is where the lines cross. It happens to be at (1,3).

Answer 5

get y by itself.
y=-3x+6 (recognize y=mx+b form?)
-y=-3x
(multiply by -1 to get positives)
y=3x+0

Answer 6

get the 2 lines in y=mx+b form using algebra... You SHOULD know what you're doing by then...!