Question

Find the slope and the y-intercept of the equation 4x + 5y = -9.
MEDAL WILL BE GIVEN

Answer 1

okay so how would you normally go about finding the slope of an equation?

Answer 2

y=mx+b?

Answer 3

Yes, that's right. The first step is to solve for y in terms of x.
So 4x+5y=-9

5y=-4x-9

y=-4/5x-9/5

Answer 4

now you have y=mx+b; y=-4/5x-9/5

Answer 5

what's your m?

Answer 6

-4/5?

Answer 7

Yep you got it

Answer 8

only thing left in the problem is to find the y intercept. Do you know how to do that?

Answer 9

A line parallel to the A.Y int. Or B.X-Int has no defined slope, and a line parallel to the A.Y int. Or B.X-Int has a slope of zero? do you know that

Answer 10

don't you still need to find the y intercept?

Answer 11

it was -9/5

Answer 12

oh good. okay you got it.

Answer 13

well, when does a line have a slope of zero?

Answer 14

undefined?

Answer 15

let me rephrase the question. what is the slope of a horizontal line?

Answer 16

0?

Answer 17

you are right but why?

Answer 18

I don't know parallel? No slope?

Answer 19

a horizontal line has the same why everywhere along the line. the only thing that changes is the x.

Answer 20

y*

Answer 21

so by the slope formula: y2-y1/x2-x1=slope=0 because y2-y1=0

Answer 22

y2-y1=0 because the y never changes on a horizontal line.

so consider a vertical line where the y is always changing but the x is always the same

Answer 23

by the slope formula: y2-y1/x2-x1=slope=undefined. this is because x2-x1=0 and therefore; y2-y1/0=undefined since you can never divide by a 0

Answer 24

does that make sense

Answer 25

not really , so does a line parallel to the y axis has no defined slope?

Answer 26

yes

Answer 27

and a line parallel to the x-axis has a slope of zero?

Answer 28

yes

Answer 29

If a line with a slope of -2 crosses the y-axis at (0, 3), what is the equation of the line?
would it be y+2x=3?

Answer 30

yes