Final answer:
The solution to the system of equations by graphing is found by plotting both equations on a coordinate plane. The first equation is converted to slope-intercept form and graphed, while the second equation is a horizontal line. Their point of intersection is the solution, which is (12, 1).
Step-by-step explanation:
To solve the system of equations by graphing, let's first rewrite the equation 'x - 3y = 9' in slope-intercept form, which is 'y = mx + b' where 'm' is the slope and 'b' is the y-intercept. We solve for 'y' and get 'y = rac{1}{3}x - 3'. Now, the second equation 'y - 1 = 0' simplifies to 'y = 1'. This is a horizontal line that crosses the y-axis at 1.
To graph 'y = rac{1}{3}x - 3', pick several values of 'x', substitute them into the equation, and solve for 'y' to find corresponding points. Plot these points on a coordinate plane and draw a line through them.
The slope is ¼, which means 'rise over run' is 1 for every 3 units of 'x'. To graph 'y = 1', draw a straight line parallel to the x-axis that crosses the y-axis at 1.
The solution to the system is the point where the two lines intersect. Since 'y = 1' is a horizontal line, it intersects 'y = rac{1}{3}x - 3' at the point where x satisfies ¼x - 3 = 1. Solving for 'x' gives 'x = 12'. Therefore, the solution to the system of equations is (12, 1).