Question

The graph below shows a line segment XY.

graph of line XY going through ordered pairs negative 2, 4 and 1, negative 5

Which of the following equations best represents the line segment XY?

y = -3x + 2

y = -2x + 1

y = -3x - 2

y = -2x - 1

Answer 1

Its decreasing so im guessing it will be either b or c

Answer 2

can u find the slope m = ?

Answer 3

-3?

Answer 4

equation for straight line
y = m.x + c , m is slope, c is where the line intersects with the Y-axis

Answer 5

isn't it y=mx+b?

Answer 6

m= -3 is correct , what is c?

Answer 7

same thing, sorry i should have used b instead

Answer 8

and b is the y intercept right?

Answer 9

yes

Answer 10

-2?

Answer 11

correct :)

Answer 12

so the answer is c?

Answer 13

correct

Answer 14

Thank You! By any chance can you help me with another? Its the same type of question.

Answer 15

sure, btw m = (y2 - y1)/(x2 - x1)

Answer 16

yes that is point-slope right?

Answer 17

i call it slope, not sure what ur level of maths call it

Answer 18

and the question is about perpendicular lines just to let you know u up for the challenge?

Answer 19

damn... me no like challenge :)

Answer 20

Choose the slope-intercept equation of the line that passes through the point shown and is perpendicular to the line shown.

line through the points 0 comma 6 and negative 2 comma 0 with a point 6 comma 2 not on the line

y = one thirdx

y = -one thirdx + 4

y = 3x + 20

y = -3x - 16

Answer 21

lol

Answer 22

what was the rule for slopes of 2 lines that are perpendicular ?
was it m1.m2 = -1 ?

Answer 23

im not sure lol

Answer 24

the slope of line 1 is what?
m1 = (6-0)/(0- -2) = 6/2 = 3

Answer 25

3/1

Answer 26

m2 = -1/3 from the rule I stated above

Answer 27

oh ok

Answer 28

so its the exact oppisite

Answer 29

{x=t2+2y=t2−4

Write both equations in terms of t²:
{t2=x−2t2=y+4

Now setting them equal to each other, you have
x−2=y+4y=x−6
@mathman123

Answer 30

now u need to find another point for line 2 to be able to draw it, so u have 1 point which is (6,2) and its slope -1/3
can u find another point using this formula
m2 = (y2-y1)/(x2-x1) by sustituting
m2 = -1/3
y1 = 2
x1 = 6

???

Answer 31

so what does m1 equal

Answer 32

m1 is the slope of the first line, we found it above = 3/1 = 3

Answer 33

and y2

Answer 34

oh ok

Answer 35

y2 is the y coordinate of a point on the second line
hold on let me draw u a picture, ok?

Answer 36

ok

Answer 37

is it perpendicular?

Answer 38

yes sorry my drawing isnt perfect

Answer 39

lol

Answer 40

so wouldn't the slope be the exact opposite?

Answer 41

yes u r right in a sense it is oppsite, instead of m1 = 3 it is -1/3 i.e the negative of the reciprocal of m1

Answer 42

yea that's what I meant lol sorry I should've explained *opposite* better

Answer 43

m2 = (y2-y1)/(x2-x1)
m2 = -1/3 , y2 = 2, x2 = 6
so
-1/3 = (2-y1)/(6-x1)
from the above can u find x1 and y1 ?

Answer 44

uh im not the best at point slope but ill take a go at it