What is the y-intercept of a graph with the points (-1, -2) and (4, 6)?

Question

The graph is linear.

Answer 1

Start by finding the slope of the graph: rise over run. To find this, take the y point of the second set (6) and minus the y point of the first set (-2). Divide this answer by the x point of the second set (-1) minus the x point of the first set (4). You now have the slope. The standard equation for a linear graph (what you have here) is y = mx + b where y is the y point, m is the slope, x is the x point, and b is the y intercept! So from here, plug in the slope you calculated, one of the two sets of points and solve for b.

Answer 2

I assume that you meant "line" instead of graph, because there are infinitely many graphs with the points (-1, -2) and (4,6).

We need to solve for the equation of the line, y = mx + b, where m = slope and b= y-intercept.

Recall that the formula to get slope for a set of points (x1,y1) and (x2,y2) is as follows:
m= (y2 - y1)/(x2 - x1)
m = (6 - -2) / (4 - -1)
m = (6+2) / (4 + 1)
m = 8/5

From here, we use the "slope equals slope" method, where we substitute y2 and x2 with y and x, and use any one of the given coordinates, use the slope formula, and equate it to the slope we calculated above.

8/5 = (y - -2)/(x - -1)
8/5 = (y+2)/(x+1)
(8/5)(x+1) = y+2
8/5x + 8/5 = y + 2

Therefore, y = 8/5 x + 8/5 - 2
y = 8/5 x + 8/5 - 10/5
y = 8/5 x - 2/5

Therefore, seeing as that line is now in y-intercept form, we see that the y-intercept is -2/5.

Answer 3

I think it's -2/5
slope is 8/5
So lets plug a point in (how about 4)
y= 8/5x - 2/5
y= 4 * 8/5 -2/5
y= 32/5 -2/5
y= 30/5 or 6
So -2/5 checks out

Answer 4

(0,2)