Question

How do you find "b" in the equation y=mx+b? (On a graph)

Answer 1

you need the slope and the two points

Answer 2

The equation i have is y=3x+ (blank). The points are (-1, 1), and (0,4).

Answer 3

which point crosses the y intercept

Answer 4

(0,4)

Answer 5

plug that into the equation by replacing the x and y

Answer 6

So it would be 0x+(blank)=4?

Answer 7

first find you slop using your two points

Answer 8

So it would be y/x, and that is 4/0?

Answer 9

i think your b would be 4

Answer 10

So the answer would be y=3x+4?

Answer 11

i think so try graphing it

Answer 12

For the question there is already a graph. I just need to figure out the equation.

Answer 13

graph you equation and see if it matches

Answer 14

How would I confirm that y=3x+4 is correct for the graph?

Answer 15

Oh, yes it matches! Thank you very much!

Answer 16

no problem

Answer 17

Just a quick recap :)
(For future reference)

If you are given a graph, and you are looking for the equation in the form y=mx+b

First thing you have to know is m stands for slope.
To find the slope from the graph:
1. Pick two points
2. Plug them in the formula \(\sf \Large m=\frac{y_2-y_1}{x_2-x_1}\)

Second thing you have to know is "b" stands for y-intercept (0, y).
To find the value of the y-int, look from your graph and anything that passes through the y axis will be your y-intercept or b.

Now, once you find the m (slope) and the b(y-int), you can easily replace them in the general formula \(\sf y=mx+b\) ^_^