we have
x + 2y = 20
The linear equation represent the equation of a line
If a ordered pair is a solution of the equation, that means that the ordered pair lies on the line
so
Find a ordered pair that represents a solution
Assume the value of x
so
For x=1
substitute in the equation
(1)+2y=20
solve for y
2y=20-1
2y=19
y=19/2
y=9.5
therefore
