Question

Consider the line whose equation is 4x – 8y = 8.

Write the equation of the line, in point-slope form, that is perpendicular to the
line and passes through the point (1, 2).

Answer 1

Point slope form is defined as y - y1 = m(x - x1)

Answer 2

Find the slope which is y2-y1/x2-x1

Answer 3

1/2

Answer 4

Plug your slope back into the equation

Answer 5

y=y1=1/2(x-x1)

Answer 6

I find it easier to use standard form which is y = mx+b

Answer 7

m = slope

Answer 8

@satellite73 help i am confused

Answer 9

We will start over... have you found y?

Answer 10

2?

Answer 11

Rewrite the equation in standard form as y =

Answer 12

2=1/2x-1?

Answer 13

No... it should be in the form y = mx+b

Answer 14

y=1/2x-1

Answer 15

Here is how u want to approach this. I can't tell you are close, just little mistakes here and there I sounds like.

Answer 16

That is what I was trying to explain. Thanks Demo

Answer 17

this is the question right
Write the equation of the line, in point-slope form, that is perpendicular to the line and passes through the point (1, 2).?

Answer 18

yss

Answer 19

did you get the answer, or do you still need help?

Answer 20

still need help

Answer 21

ok but you did most of it already
you found the slope of \[4x – 8y = 8.\] is \(m=\frac{1}{2}\)

Answer 22

the perpendicular line has a slope that is the "negative reciprocal" i.e. flip it and change the sign
the negative reciprocal of \(\frac{1}{2}\) is \(-2\)

Answer 23

now the question really becomes
find the equation of the line with slope \(-2\) through \((1, 2)\)

Answer 24

for that you use the "point slope" formula
\[y-y_1=m(x-x_1)\] which in our case is
\[y-2=-2(x-1)\]

Answer 25

to put it in the "slope intercept" form, solve for \(y\)
the steps are always the same
first multiply out on the right and get
\[y-2=-2x+2\] then add \(2\) to finish with
\[y=-2x+4\] and that is done

Answer 26

ok thanks i know get it

Answer 27

good
not too hard
you got another one to try?

Answer 28

i have a differnt one on how to graph a eqation

Answer 29

like the last one?

Answer 30

um like the last one we graphed kinda x+3y<6 that is a greater than or equal sign

Answer 31

\[x+3y\leq 6\] i.e. "less than or equal to" right?

Answer 32

yes

Answer 33

ok lets do this the easy way

Answer 34

if \(x=0\) you get \(3y=6\) or \(y=2\) so we know \((0,2)\) is on the graph, where the line hits the \(y\) axis

Answer 35

if \(y=0\) you get \(x=6\) so you know \((6,0)\) is on the graph, where the line crosses the \(x\) axis
lets plot those two points only

Answer 36

now since it is \(x+3y\leq 6\) the graph is not just a line but the whole region BELOW the line

Answer 37

shade in all stuff underneath

Answer 38

ok so thats it

Answer 39

yup

Answer 40

k thanks

Answer 41

yw