Question

Can someone p[lease explain to me how to graph linear inequalities?

Answer 1

\[4x+5y \le 20\]

Answer 2

The first step is graphing a line. do you know how to do that ?

Answer 3

Do you know how to graph
4x+5y=20
?

Answer 4

That's just one of the equations that I have to use but I don't think that I can just graph it using the form that it's in... I don't know how to change the form, what form it needs to be changed into, or how to graph it :(

Answer 5

to plot a line, all you need are two points on the line, then you draw a line through those two points.

if the equation is already in point-slope form (yours is not), it's a bit easier to find two points.

But in your problem, replace x with 0 . can you do that ? what do you get ?

Answer 6

So I have to convert it into y=mx+b form?

Answer 7

@skullpatrol

Answer 8

you could, but it's easier to just find two points. one way is to replace x with 0 in your equation

4x+5y=20

can you do that ?

Answer 9

\[4(0)+5y \le20\]

Like this?

Answer 10

yes, but we are just plotting the line (for now) so
4(0) + 5y = 20

Answer 11

you know 4*0 is 0, right ?

Answer 12

0+5y is just 5y (adding 0 does not change anything)

4(0) + 5y = 20
becomes

5y= 20

now, divide both sides by 5
can you do that ?

Answer 13

Rearrange the equation so "y" is on the left and everything else on the right.
Plot the "y=" line (make it a solid line for y≤ or y≥, and a dashed line for y< or y>)
Shade above the line for a "greater than" (y> or y≥) or below the line for a "less than" (y< or y≤).

Answer 14

okay thank you all