Question

Write an equation for the line described. Write it in standard and point intercept form(if possible)
through (1,3), m=-2
through (-5,4), m=-3/2
i need a little explanation also, if you can give it... studying for a test.

Answer 1

ok so you get those in standard form by first using this formula: \[(y - y_{1}) = m (x - x_{1})\]

Answer 2

so, for the first equation, this is (y - 3) = -2(x - 1)

Answer 3

y - 3 = -2x + 2

Answer 4

to get it into standard form (Ax + By = 0) move 2x to the other side, giving you 2x + y - 3 = 2

Answer 5

depending on qhat the quiz asks you, the final answer will either be 2x + y = 5 or 2x + y - 5 = 0.

Answer 6

*what

Answer 7

Did you mean slope intercept when you said point intercept?

Answer 8

yes.. sorry

Answer 9

So the second one.
Standard form : y-4=-3/2(x-(-5))

Answer 10

I get confused with the fractions?

Answer 11

And all those negatives are throwing me off..

Answer 12

Lots of people have trouble with it. We know that a negative negative is a positive. That gives you y - 4 = -3/2(x + 5)

Answer 13

Then, you multiply x and 5 by -3/2

Answer 14

a positive and a negative multiplied together is a negative. That gives you -3/2x - 15/2

Answer 15

-15/2 is reached when you multiply -3/2 and 5/1

Answer 16

do you understand that?

Answer 17

Yes, so far so good.

Answer 18

Then I need to put it in standard form..

Answer 19

Well, that wasn't a complete point slope form, so let me explain. Above you gave me y - 4 = -3/2(x - (-5)) Your complete slope form would be y = -3/2(x - 1), getting the 4 on the correct side. So, we'd have -3/2x + 3/2

Answer 20

do you understand how I got that?

Answer 21

Why dont you want it in the same form as the previous one? ax=by=0?

Answer 22

sorry ax+by=0

Answer 23

When I convert 4 into a fraction is that 8/2?

Answer 24

When I subtract that 8/2 from the right side I come up with -3/2x-7/2?

Answer 25

hold on a second

Answer 26

it's easier to set up standard form if you first have it in slope intercept form.

Answer 27

no, you want to get the constant on the right side of the equation BEFORE you multiply the whole thing by -3/2.

Answer 28

y = -3/2 + 3/2

Answer 29

constant meaning?

Answer 30

Constant is a number with no variables; 3a would be a coefficient, 3 is a constant.

Answer 31

where and how are you getting that +3/2

Answer 32

ok, let me explain

Answer 33

y-4=-3/2(x=5) can you take me from there?

Answer 34

Okay. (you were right, I was getting confused.)

Answer 35

(x+5)

Answer 36

first you add 4 to each side, giving you y = -3/2(x + 9)

Answer 37

multiply both terms by -3/2, giving you -3/2x -27/2

Answer 38

move -3/2x to the left side of the equation, giving you 3/2x + y = 27/2

Answer 39

sorry, -27/2

Answer 40

depending on the curriculum, your final answer would be 3/2x + y = -27/2 or 3/2x + y + 27/2 = 0

Answer 41

let me rewrite it out myself and see if that's the right answer

Answer 42

My book gives me an answer of 3x+2y=-7

Answer 43

Do I just multiply by 2 to clear the fraction?

Answer 44

no, when you're talking about lines you don't take out the fraction

Answer 45

but let me work it out and see if I can get it that way multiplying by 2

Answer 46

ok, it seems to me that your book does want you to multiply by 2, but my curriculum didn't teach me that

Answer 47

Ok.. thank you so much for being patient with me...this helped!

Answer 48

you're welcome :D