help with graphing linear functions!!! (not looking for answer, just help!!!!)?

Question

the question is "draw the graph of F(x)=3-2x in the domain -1 is equal or less than x is equal to or less than 4"

do i just sub in -1 for x in the formula given get the answer and then the point on the line is -1 and the answer??

cheers!!

and then i keep subbing in until i reach 4

is that right?

but when i do that the line isnt straight!!, i checked the equations twice and they are right!

i know i said i wasnt looking for the answer but could you work it out and see if you got the same answer as me??
i dont know where i went wrong!

cheers for that the two first answerer's!!, very very very very much appreciated!!!!

cheers again!

Answer 1

When x = -1, f(x) = 5 so you have point (-1,5)
When x = 4, f(x) = -5 so you have point (4,-5)
Draw a line between these two points and you have the answer.

Just use yhe two end-points. You need not evaluate each point between -1 and 4.

Answer 2

The key to understanding the graph of linear equation is understanding the slope and intercept. Find the slope (m) and intercept (b), by putting the equation into the form y = mx +b.

F(x) = 3 - 2x therefore becomes y = -2x + 3

where:
slope (m) = -2
intercept (b) = 3

From here, you can see that the y-intercept (the point where the line crosses the y-axis) is at y = 3. So put a point at x=0, y=3.

Next, note that the slope is -2. The slope says that every time x increases by 1, y decreases by 2. So, from x=0, y=3, move right 1 and down 2 and put a point at x=1, y=1.

Then draw the straight line between the two points.

Answer 3

Hi,
Yes, you have the right idea. But this is a linear equation, so you should have a straight line. Since the slope is negative, -2, your line should be sloping downward. Actually, you only need two points for a straight line, but we often use three for various reasons. You can read off one of the points from the y-intercept. It crosses the y-axis at y=3, so that point will be (0,3). Now, let's make a table to enter the points into and do the two end points.
x___|__f(x)___
-1__|__5_____
0___|__3_____
4__|___-5____
(Sorry about the ratty looking table.)
Here are the calculations:
f(-1) = 3 - 2(-1) (Make sure you got this sign correct.)
= 3+2
=5

f(0) = 3-2(0)
=3

f(4) = 3-2(4)
=3-8
=-5
Hope this helps.
FE

Answer 4

Q1. f(x) = –3x + 7 and Q2. f(x) = –3x2 + x – 5 permit y = f(x) so we get: y = –3x + 7 <-- Eq a million y = –3x2 + x – 5 <-- Eq2 Now you're waiting to devise on x-y coordinate equipment In Eq a million permit x =0 and remedy for y getting y = 7 so (0,7) is one element on the line of Eq a million. Now permit y =0 and remedy for x getting x = 7/3. So now you have the element (7/3, 0). Plot those 2 factors and draw a line via them, extendig it so a methods as you like. that's the graph of Eq a million. Now in you 2d equation evidently like -3x2 is meant to be -3x^2 or 3x squared. if that's the case, that could be a quadratic equation and is no longer linear. it would be a parabola. If -3x2 capability -6x then the equation is linear and can be y= -5x-5, so which you would be able to desire to remedy this the comparable way Eq a million replaced into solved. yet -3x2 is a very unusual thank you to jot down -6x and so I even have serius doubts as to that interpretation.

Answer 5

That would be the way I would do it. You would then have a line extending from values of x from -1 to 4.