Question

I do not understand how to graph 3x-y<4. I thought I was supposed to substitute 0 for x and solve for y and then substitute 0 for y and solve for x to come up with the intercepts. When I do that I end up with y=4 (0,4) and then I end up with 3x = 4 and I don't know what to do next because 3 won't go into 4.

Answer 1

to graph 3x-y<4, we'll need to first graph 3x-y=4 which is the boundary line

Answer 2

plugging in x = 0 leads to

3x-y=4
3*0-y = 4
0-y = 4
-y = 4
y = -4

so it should be (0,-4) instead of (0,4)

Answer 3

Oh, I didn't know what to do with the negative sign so i ignored it

Answer 4

now let's plug in another x value, say x = 1

3x-y=4
3*1-y = 4
3-y = 4

solve for y to get y = ??

Answer 5

What do I do with the 3?

Answer 6

to move that over, you subtract 3 from both sides

Answer 7

-1

Answer 8

yes if x = 1, then y = -1

Answer 9

so the two points (0,-4) and (1,-1) are on the graph of 3x-y=4

Answer 10

plot the two points and draw a straight line through both of them. Extend the line out as far as you can in both directions

Answer 11

thank you. It's always something so small that I do wrong.

Answer 12

do you know how do to the shaded region?

Answer 13

yes

Answer 14

ok great, just checking