How do i know what to substitute for x?

Question

Im taking an intermidiate algebra class and working on Ch 8: Systems of Equations i have to solve by graphing. for example, x + y= -3 and 4x - y= -2. Now, I solved for y on both equations which has an outcome of y = -3 - x and y = 2 + 4x. My problem now is that i have to make three ordered pairs for each equation just that i dont know what has to be used to substitute for x. Ive gone through my book i do see there are various ways but how do they come upon choosing those intergers. Im so confused please help.

Answer 1

Graph the line and then go into your table properties and see where x and y are. Choose any those are your points.

Answer 2

The cool thing about linear equations is that you can basically substitute any value you want for x. With simple equations like you have, it's best to substitute integers that are close together and near 0, so numbers like -3, -2, -1, 0, 1, 2, 3. That makes them easy to plot and easy to draw lines through. Some people prefer to use the x-intercept and y-intercept. If you set x=0 and find y, then set y=0 and find x, you'll already have two easily calculatable coordinates.

If you're having more trouble solving these equations after that step...

The point to substituting in these values for x is to get points that you can then draw a line through (connecting the dots). Once you draw both lines, you find the point at which they cross and voila, you have the solution.

If you take the x value of the point at which they cross and substitute into both equations, you should receive the same value for y.

Answer 3

x=-1
as
-3-x = 2+4x
5x = - 5
x = -1

Answer 4

This may help
http://www.freemathhelp.com/
i just googled it.
Have a great day, and good luck

Answer 5

substitute x with xfiles