Question

Consider the line
-9x-5y=7
.
Find the equation of the line that is perpendicular to this line and passes through the point
−3, 2
.

Find the equation of the line that is parallel to this line and passes through the point
−3, 2
.

Answer 1

it is easier if you convert the original equation into the form

y = mx + c

can oyu do that first?

Answer 2

-5y=-9x+7

Answer 3

no quite - you need to be careful of the - sign

Answer 4

well can you help me

Answer 5

I am helping - you are nearly there

you just made a simple error when you arranged the formula.

Have a look again at what oyu did - be careful of the minus sign....

Answer 6

5y=9x-7

Answer 7

no sorry - that is still not correct . slow down a little...

-9x-5y=7


first add 9x to each side....


then divide each side by -5

Answer 8

ok i see so -5y=9x+7 = y= -9/5x+7/5

Answer 9

ok that's right now

this form tells you about the line

it is in th e form y=mx +c

the value of m is the slope of the line - what is th eslope in this case?

Answer 10

-9/5

Answer 11

OHH it's still not right

you divide by -5 so it's
y= -9/5x -7/5 OK?

you are correct about the slope tho - it's -9/5

Answer 12

so oyu probably know if the slope of a line is m

what is the slope of a perpendicular line?

Answer 13

5/9

Answer 14

good - that's right

so now oyu need to find a line with that slope passing through (-3,2)

Answer 15

so plug in the coordinates ??

Answer 16

so oyu know the equation of that line is y = 5/9 x +b

and ypou know that when y = 2 then x = -3

Answer 17

okay now i understand

Answer 18

yes plug in those values ot solve for b

Answer 19

2=5/9(-3)+b

Answer 20

-2

Answer 21

ugh i -2=5/9(3)+b

Answer 22

and for the second part the parallel line has the SAME slope as the original , but passes through the point (-3,2) so do the same for that equation

Answer 23

2=-9/5(-3)+b

Answer 24

-2 =-9/5(3)+b

Answer 25

you need to solve for b in both cases

Answer 26

oh

Answer 27

how do i do the fraction again

Answer 28

you wrote this for the first part

2=5/9(-3)+b

so 2+(15/9) = b

simplify that

Answer 29

b=11/3

Answer 30

its asking for the equation of the line so i dont solve it

Answer 31

correct

so the formula is
y = mx + b

m =5/9, b= 11/3

Answer 32

y=5/9x+11/3

Answer 33

that is correct