1) x + y = 8
2) x - y = 6
put both equations into slope-intercept form:
x + y = 8
y = -x + 8
slope = -1, y-intercept = (0, 8)
x - y = 6
y = x - 6
slope = 1, y-intercept = (0, -6)
As a check, I'll determine the point of intersection algebraically:
1) x + y = 8 or y = 8 - x
2) x - y = 6
substitute eq(1) into eq(2):
x - (8 - x) = 6
2x - 8 = 6
2x = 14
x = 14/2 = 7
using eq(1):
y = 8 - 7 = 1
check using eq(2):
7 - 1 = 6
x = 7, y = 1
point of intersection = (7, 1)