Question

how do you write an equation from looking at a graph that already has the line drawn?

Answer 1

use the slope intercept form (y = mx + b), where m represents the slope and b represents the y-intercept, look at the graph and find they y intercept, plug this value in for b, then find the slope and plug this value in for m

Answer 2

ok oneBIG problem, no has ever show me how to read graphs so I don't have a clue what I am looking at.

Answer 3

look at the graph where does it cross the y-axis ( the one that goes up and down)? that is what is substituted in for b

then look at the line from the y-intercept, count how many units up and how many units over you have to go to get to the next point (this is the slope, plug it in for b), (example: if you count up 3 and right 5 the slope is 3/5)

Answer 4

ok up 3 over to the right 7 =3/7 right? then how do i figure for y=?

Answer 5

y=mx + b, where m = slope, and b = y-intercept

Answer 6

ok m = 3/5 and b=3???

Answer 7

so y=3/5x + 3?

Answer 8

yes

Answer 9

cool I got one right. thank you very much

Answer 10

congratulations

Answer 11

i had another one to do and the way you explained it I was able to do that one rather quickly

Answer 12

now if u can help me do the equation and then draw the line on a blank graph y=-2x+5

Answer 13

m = -2, and b = 5

so go up 5 units on the y-axis and put a point, then count from the point (up 2, left 1) or (down 2, right 1) to find more points, then connect them to graph the line

Answer 14

ok how do u know if u go up 2 or down 2?

Answer 15

if the slope is negative the line will tilt up on the left and down on the right, so (up 2, and left 1) will the same as (down 2 and right 1)

Answer 16

ok i see. thanks. now the next one is different. x+5y=10

Answer 17

you need to solve for y, so move the x to the right (5y = -x + 10), then divide all the terms by 5 (y = -1/5x + 2), so the y-intercept is 2, and the slope is -1/5 (up 1, left 5 or down 1, right 5)

Answer 18

ok thanks