Question

Write the equation of the line which passes through (2, –3) and is perpendicular to y = 4x + 7 in standard form.

Answer 1

what's the slope of the equation -> y = 4x + 7 ?

Answer 2

wud 7 be the slope

Answer 3

http://www.mathexpression.com/image-files/slope-intercept.png

Answer 4

4 wud be slope

Answer 5

ok, so your other line is PERPENDICULAR to this one

Answer 6

bearing in mind that perpendicular lines have NEGATIVE RECIPROCAL slopes

so if this one has a a slope of "4"
the other slope would be

reciprocal of 4
1/4

negativize that
-1/4

Answer 7

so, now you know it passes through (2, -3) and has a slope of -1/4
to get the line, use the point-slope form and solve for "y"
http://www.coastal.edu/mathcenter/HelpPages/Line(Point-Slope)/img002.GIF

Answer 8

the point slope wud be ? -1/4

Answer 9

ahemm, read above

Answer 10

the example in the picture, shows how to use the point-slope form :)

Answer 11

ok so -1/4 is my slope

Answer 12

no 4 is my slope

Answer 13

you have 2 lines, you have the equation for one " y = 4x + 7"
and you only know about the OTHER LINE that it passes through (2, -3)
and is perpendicular to the line " y = 4x + 7"

Answer 14

if y = 4x + 7
has a slope of "4"
the perpendicular line to it will have a slope of NEGATIVE RECIPROCAL of 4

Answer 15

i got y=4x-5 so far

Answer 16

4 is the slope of the GIVEN line
the slope of the perpendicular line that passes through (2, -3) is -1/4

Answer 17

so i just forgot the -1/4

Answer 18

yes, the rest of the procedure is good though, just need to change the 4 to -1/4

Answer 19

okay so will my final y=4x-5
will tht be changed to y=-4x-5?

Answer 20

$$
\text{what do you get from}\\
y-(-3) = -\cfrac{1}{4}(x-2)
$$

Answer 21

a negative

Answer 22

ahemm, yes the slope will be negative, meaning the function is "descending"

Answer 23

so y = -4x-5

Answer 24

if you just solve \(\large y-(-3) = -\cfrac{1}{4}(x-2) \) for "y", you'd know :)

Answer 25

when i did tht i got y+3=-2.25

Answer 26

well, the "x" seem to have got the axe hehe

Answer 27

-1/4x

Answer 28

well a negative plus a negative wud be a positive number. So I believe it would become positive.

Answer 29

$$
\text{what do you get from}
y-(-3) = -\cfrac{1}{4}(x-2)\\
\implies y+3 = -\cfrac{1}{4}x+\cfrac{2}{4} \implies
y+3 = -\cfrac{1}{4}x+\cfrac{2}{4}\\
\implies y = -\cfrac{1}{4}x+\cfrac{1}{2}-\color{blue}{3}\\
\color{blue}{3 = \cfrac{6}{2}}\ \ thus\\
\implies y = -\cfrac{1}{4}x+\cfrac{1}{2}-\color{blue}{\cfrac{6}{2}}\\
\color{green}{y = -\cfrac{1}{4}x-\cfrac{5}{2}}
$$

Answer 30

wud the y=4x-5 be the final answer

Answer 31

that's the line

Answer 32

Write the equation of the line which passes through (2, –3) and is perpendicular to y = 4x + 7

Answer 33

the one above in "green" is the line :)

http://fooplot.com/#W3sidHlwZSI6MCwiZXEiOiI0eCs3IiwiY29sb3IiOiIjMjIzNUM3In0seyJ0eXBlIjowLCJlcSI6Ii0xLzR4LTUvMiIsImNvbG9yIjoiI0Q2MzIxMSJ9LHsidHlwZSI6MTAwMH1d

see ^, they're perpendicular

Answer 34

okay so then y=-1/4x-5/2 is the final aswer

Answer 35

yes

Answer 36

and yes i saw they were perpendicular. thank u!

Answer 37

yw