How does changing the m in an equation written in slope-intercept form affect the graph?

Question

Also how does changing the b affect the graph?

Answer 1

The m in slope intercept form y = mx + b is the slope.  If you increase m, the line becomes more steep (left to right).  If you decrease m, the line becomes less steep (left to right).

The b in slope intercept form y = mx + b is the y-intercept- the place where the line crosses the y-axis.  If you increase b, you shift the entire line upward without changing its slope.  If you decrease b, you shift the entire line downward without changing its slope.