Question

HELP???!!!!!
Write an equation of a line perpendicular to line CD below in slope-intercept form that passes through the point (−1, 6).

Answer 1

y = −0.5x − 5.5

y = −0.5x + 5.5

y = 2x + 13

y = 2x − 13

Answer 2

@phi

Answer 3

@esshotwired

Answer 4

what is the slope of the line in the graph ?

Answer 5

in other words, what is the change in y divided by the change in x ?

Answer 6

Y2-Y1 OVER X2-X1
(1,1),(3,5)
5-1 OVER 3-1
4 OVER 2=
2

Answer 7

now what is the slope of the perpendicular line ? (ring any bells ?)

Answer 8

-2

Answer 9

that is just -1 times 2

we did this an hour ago: flip and times -1

Answer 10

-0.5

Answer 11

can you finish ?
you can do a few things:
1) use y - y0 = m(x - x0) where (x0,y0) is a point you know is on the line i.e. (-1,6)
or
2) write down y = mx + b, replace x and with with -1 and 6 and solve for b
or
3) check the two choices with a slope of -0.5, and see which works for (-1,6)

Answer 12

I forget how to do it

Answer 13

which 2 choices have a slope of -.5 ?

Answer 14

huh

Answer 15

the question is
****
Write an equation of a line perpendicular to line CD below in slope-intercept form that passes through the point (−1, 6).
***

you figured out the slope is -.5

you listed 4 possible answers up above. which of the four could be the answer (because they have a slope of -0.5 ) ?

Answer 16

you can test each one. replace x with -1 in the equation and do the arithmetic. if you get y=6 that is the correct equation

Answer 17

the first one and the second one

Answer 18

test the first equation to see if (-1,6) is a point on the line

when x = -1 you get
y = -0.5*-1 - 5.5
if you simplify that , do you get y=6 ?

Answer 19

nope i got -5
the second one i got 6

Answer 20

@phi

Answer 21

that means the second equation is the answer.
it has the correct slope (of -½) and it goes through the point (-1,6)