Answer:
1) y=6
Explanation:
The equation y=mx+b is called slope-intercept because it tells us the slope,m, and y-intercept ,b.
The equation y=a is a horizontal line and goes through a on the y-axis. Horizontal lines have a slope of zero.
The equation x=b is a vertical line and goes through b on the x-axis.
Vertical lines have an undefined slope.
1) y=6 is horizontal so it's slope is 0
2) x=6 is vertical so it's slope is undefined
3) y=2x has slope 2
4) x+y=1 can be put into the form y=mx+b to determine the slope.
Subtract x on both sides:
y=-x+1
The slope is -1.