Question

Graphing help???? Please!!!

Write the equation of the line that is parallel to the line 3x - y = -3 and passes through the point (4, -2).

y = -one thirdx - 6

y = -one thirdx - 14

y = 3x - 6

y = 3x - 14

Answer 1

1st find the slope of given line.

Answer 2

Slope of given line will be equal to the slope of require line.

Answer 3

\[y1 - y2 \over x2 - x1\]

Answer 4

Then put the value of slope in general line equation y= mx +c

Answer 5

I use this to find the slope right?

Answer 6

this formula is for finding the slope in between two points.

Answer 7

you can just put 3x - y = -3 into y = mx + b form, and the slope is in the m position

Answer 8

there is another simple technique , that is use the general line equation y = mx +c
here m is the slope.

Answer 9

okay but what does c stand for in you equation?

Answer 10

the last letter, whether it is c or b is the y intercept

Answer 11

c is the intercept of the line with the y- axis.

Answer 12

are you getting this thing?

Answer 13

Yeah I think that I understand
the equation that I need to use would look like this then right?
y = -3 * 4 +-2

Answer 14

no , tell me what is value of slope in the given line?

Answer 15

3x - y = -3 --- put this in y = mx + b form

3x + 3 = y -- rearrange
y = 3x + 3

when you put your equation in y = mx + b form, the m is your slope.
so in y = 3x + 3, the slope is 3.

Do you understand so far ?

Answer 16

@naga447 .follow the procedure given by @texaschic101 .

Answer 17

okay but did you mean to switch the -3 to a positive 3?

Answer 18

let me do this step by step..
3x - y = -3 (add y to both sides)
3x - y + y = y - 3 (combine like terms)
3x = y - 3 (add 3 to both sides)
3x + 3 = y - 3 + 3 (combine like terms)
3x + 3 = y
rearranged is :
y = 3x + 3

understand ? And the number in the m position is the slope.

have I lost you ?

Answer 19

Yeah I believe that I get it
the slope is 3 correct?

Answer 20

yes..the slope is 3. And since we are looking for a parallel line, the slope will remain the same. If we were looking for a perpendicular line, it would be different.

So now we have to use a slope of 3.
And we have (4,-2) as our points.

Now we can sub this back into y = mx + b
slope(m) = 3
(4,-2)...x = 4 and y = -2
and since we know the slope is 3, we will be looking for b, the y intercept.
so we sub
y = mx + b
-2 = 3(4) + b

can you finish and solve for b ?

Answer 21

-2 = 3 * 4 + b
-2 / 4 = 3 + b
-0.5 = 3 + b
3 - -0.5 = b
3.5 = b?

Answer 22

-2 = 3(4) + b
-2 = 12 + b --- subtract 12 from both sides
-2 - 12 = 12 - 12 + b -- combine like terms
-14 = b

what you do on one side of the equal sign, has to be done on the other side. I had to isolate b, and to do this, I had to subtract 12 from both sides so that the 12 on the right side gets eliminated.

Do you understand so far ?

Answer 23

so we have found our slope to be 3 and our y intercept to be -14.
And in y = mx + b form, the m is the slope and the b is the y intercept.
So the parallel line will be :
y = 3x - 14

any questions ?

Answer 24

if you have any questions, please ask. I am here to help you :)

Answer 25

That makes a lot more sense then what I was trying to do! Thank you very much for helping me out and putting up with my stupidity!