Slope Intercept Form?

Question

Give coordinates of the point where the line for equation crosses the y-axis.
y = 3x + 4
Also write equation for the line passing through each pair of points. (3,8), (2,6)

Answer 1

1) Plug in x=0, and you get y = 3(0) + 4 = 4.

2) First, compute the slope, m = (y2-y1)/(x2-x1) where (x1,y1) and (x2,y2) are the given points. In this case, m = (8-6)/(3-2) = 2/1 = 2.

Then, the slope-intercept form of the equation is

y = mx + b = 2x + b,

since m=2. To get b, plug in either of the given points. You get

8 = 2(3) + b, so b = 8-6=2. The equation is y = 2x + 2.

Answer 2

1) 4

2) y = 2x + 2