System of Equations
Given the system of equations:
2x + y = -6
y = 1/4x + 3
It's required to solve it by graphing.
The graph of a line can be drawn by only knowing two points of it.
To graph the first equation, solve for y:
y = -2x - 6
Now give x two values. For example, x = -5 and x = -1.
For x = -5:
y = -2(-5) - 6
y = 10 - 6 = 4
Point (-5, 4)
For x = -1:
y = -2(-1) - 6
y = 2 - 6 = -4
Point (-1, -4)
With these points, we can graph the first equation. The graph will be shown below in red.
Now graph the second equation:
y = 1/4x + 3
For x = -8
y = 1/4(-8) + 3
y = -2 + 3 = 1
Point (-8, 1)
For x = 0:
y = 1/4(0) + 3
y = 0 + 3 3
y = 3
Point (0,3)
The second line is drawn in blue below.