Question

write an equation in slope-intercept form for the line that passes through the given point and is perpendicular to the graph of the equation. (4,-2),y=3x+5

Answer 1

first off, where are you getting stuck at? ^_^

Answer 2

the whole thing

Answer 3

no problem
first lets figure out what the slope would be for a line perpendicular to the line we have been given,
so find 'm' out of your line equation of y=3x+5,
then multiply it by (-1) then flip that fraction

so for example if m=8, then I would do (-1)*8= -8, then flip it: -1/8 ^_^
can you do this procedure for your m?

Answer 4

y=-3/1-5

Answer 5

you got the slope for the perpendicular line right ^_^

Answer 6

next step is to plug in new m into the slope-intercept form
y = mx+b
y=(-1/3)x+b
now we need to plug in the point the problem gave us, and solve for b

Answer 7

sorry, m = -1/3 not -3/1

Answer 8

y = 3x + 5
perpendicular line will be negative reciprocal of the slope.
So, if the slope is 3, the negative reciprocal of the slope is -1/3.
What you do is " flip " the slope and change the sign.

Answer 9

@texaschic101 could i get you to look at another problem i'm trying to work out?

Answer 10

sure....I can't make no promises that I can do it, but I will look at it

Answer 11

so would it be 3/1

Answer 12

no....we know that the slope we need to use is -1/3. We will now use this formula : y - y1 = m(x - x1)
slope(m) = -1/3
(4,-2) x1 = 4 and y1 = -2
now lets sub
y - (-2) = -1/3(x - 4) -- distribute through the parenthesis
y + 2 = -1/3x + 4/3 -- subtract 2 from each side
y = -1/3x + 4/3 - 2
y = -1/3x + 4/3 - 6/3
y = -1/3x - 2/3 ==> your perpendicular line

any questions ?

Answer 13

then how do u do (-5,2) y=1/2x-3 because i did that one so different than you did

Answer 14

you looking for parallel or perpendicular ?

Answer 15

perpendicular

Answer 16

the slope of the line given is 1/2. But we need perpendicular slope...so flip the slope and change the sign making the slope we need -2.

you can either do it using this formula : y - y1 = m(x - x1)

or you can just use y = mx + b

(1) y = mx + b
(-5,2) x = -5 and y = 2
slope(m) = -2
now sub and find b
2 = -2(-5) + b
2 = 10 + b
2 - 10 = b
-8 = b
so your equation is : y = -2x - 8

(2) y - y1 = m(x - x1)
slope(m) = -2
(-5,2) x1 = -5 and y1 = 2
now lets sub
y - 2 = -2(x -(-5)
y - 2 = -2(x + 5)
y - 2 = -2x - 10
y = -2x - 10 + 2
y = -2x - 8

you can do it either way

Answer 17

okay thanks