Question

solve linear equation by graphing
3x+y=0
2x+y=-3

Answer 1

do you know how to graph linear functions?

Answer 2

nope

Answer 3

y = -3x for the first
y = -2x-3

Answer 4

do you know what a slop and a y intercept is?

Answer 5

slope*

Answer 6

yes

Answer 7

do you know what each variable in y = m+b is for?

Answer 8

err y = mx+b

Answer 9

in other words

what is the slope of y = -3x ?

Answer 10

@aea2213 ?

Answer 11

is the slope 0

Answer 12

no

y = mx+b
m = slope
b = y intercept

so for y = -3x we have no b value, so the y intercept is 0, and the slope is -3

make sense?

Answer 13

yea so the pair would be (0,-3)

Answer 14

nono, -3 is a slope, it is not a y value.

so we would draw a graph, and start at the y intercept, wich is (0,0) and then go down 3 to the right 1 and make a point, then go down 3 and to the right 1.......

make sense?

Answer 15

do you understand why the y intercept is (0,0)?

Answer 16

ok kinda i understand

Answer 17

because there is no y intercept

Answer 18

ok what is the slope and y intercept (ordered pair) of

y = -2x-3

Answer 19

correct

Answer 20

2 is the slope and -3 y intercept

Answer 21

well there is a y intercept, but since there is no b value, b must be = to 0

Answer 22

slope is -2

Answer 23

but wait back up a sec.

Answer 24

on the last one y = -3x is the same thing as y = -3x+0 thus our y intercept is 0
and when we talk about a y intercept we are saying x = 0 so its the ordered pair (0,0) ok?

Answer 25

now for y = -2x-3

the slope is -2 and the y intercept is -3

Answer 26

so we know the graph crosses the y axis when x = 0 and y = -3 or at (0,-3)

Answer 27

do you see why the slope is -2 and n ot 2? we always take the sign of m

Answer 28

no i dont :/

Answer 29

but so I graph (0,-3) and (-2,-3)

Answer 30

um you start at the y intercept (0,-3) and then since the slope is -2 and -2 = -2/1
and slope is rise/run we go down 2 then to the right 1. then down 2 and to the right 1....

Answer 31

ok thanks