Solve by graphing?

Question

Solve the system by graphing.?
x – 2y = 8
x + y = –1

Answer 1

You need to draw each line, which you can probably do most easily if you express them in slope-intercept form.

x - 2y = 8 ==> 2y = x - 8 ==> y = (1/2)x - 4
x + y = -1 ==> y = -x - 1

Just draw these two lines carefully, and you should be able to locate their intersection. It should be (2, -3).

Answer 2

x-2y= 8
y= x/2-4 (1)

x+y= -1
y= -x-1 (2)

Draw out graphs (1) and (2). Since they're both obviously straight line graphs (as they are in the form of y=mx+c where c is a constant), just substitute in about 3 values of x to find corresponding values of y, then plot.

The intersection, ie (2, -3), of the two graphs is the solution of the equation. (ie, x=2, y=3)

Answer 3

x -2y = 8
x + y = -1

The solution is where the lines cross is ( 2, -3 )

One line x - 2y = 8 has these 2 points ( 0, -4) and ( 8, 0 )
Other line x + y = -1 has these 2 points ( 0, -1) and ( -1, 0 )

These 2 lines cross at ( 2, -3 )

Answer 4

That just means graph the lines and see where they cross

first you'll need to put the equations above in slope intercept form by solving for y

y = mx + b

so the first equation would be y= 1/2x+4