Question

Write the equation of a line in slope-intercept form that is perpendicular to the line y=3/5x-1 and passes through the point (-9, 4).

Answer 1

@Calcmathlete mind helping with this one too? im not sure what to do with (-9,4)

Answer 2

Do you know what the relationship between perpendicular slopes is?

Answer 3

no, mind explaing?

Answer 4

Alright. Perpendicular lines have slopes that have a special relationship. The slope of a perpendicular line is the negative reciprocal. So, if the slope were persay 3, then the perpendicular slope would be -1/3. Can you find the negative reciprocal of 3/5?

Answer 5

-3/5?

Answer 6

no?

Answer 7

It would b be-5/3

Answer 8

that crossed my mind...

Answer 9

Now, just plug it into point-slope form and simplify to slope-intercept form.
\[y - 4 = -\frac53(x + 9) \implies y = -\frac53(x + 9) + 4 \implies ?\]

Answer 10

y=-5/3x-11, thanks.but im still kinda confused about the first step

Answer 11

Alright. Think about it. Let's say we have the line y = x. A perpendicular line would be y = -x right?

Answer 12

The slope of y = x, is 1. The negative reciprocal is -1. If you're confused on the reciprocal part, then it means to flip the number. So if you have 2/3, the reciprocal is 3/2. Do you get it now?

Answer 13

oh, alright, i think i got it now, might try the other one myself first. thanks again calcmathlete

Answer 14

np :)