anonymous one year ago A line through which two points would be perpendicular to the line y = 2/3x - 5/2? A. (–4, 3) and (–2, –6) B. (–4, –3) and (2, 6) C. (–4, 3) and (2, –6) D. (4, –3) and (2, 6)

1. anonymous

$y = \frac{ 2 }{ 3 }x - \frac{ 5 }{ 2 }$

2. texaschic101

can you tell me the slope of y = 2/3x - 5/2 ?

3. texaschic101

In y = mx + b form, the slope will be the number in the m position. Can you tell me the slope now ?

4. anonymous

|dw:1433342536124:dw| My drawing sucks but 3/1 I think

5. texaschic101

watch this.... y = mx + b y = (2/3)x - 5/2 the number in the m position is the slope...so the slope is 2/3 are you still following how I got that ?

6. anonymous

Yes

7. texaschic101

but we are looking for a perpendicular line...so we need the negative reciprocal slope. All that means is " flip " the slope and change the sign. So our perpendicular slope has to be -3/2......see how I flipped the slope and changed the sign ? Understand so far ?

8. anonymous

Yup, reciprocals were always the easiest thing for me XD

9. texaschic101

don't forget about changing the sign.... so our answer has to have a slope of -3/2 do you know how to find the slopes of your answer choices ?

10. anonymous

Do the same thing as you did with the question ?? Or do I do it normally

11. texaschic101

There is a formula...yes, like there wasn't enough already...probably a zillion formulas...anyways, the formula is : slope = (y2 - y1) / (x2 - x1) do you want me to show you how to label your points and find the slope ?

12. anonymous

I think I got it So like for answer A. It'd be m = (y2-y1) / (x2 - x1) m = (-6 - 3) / (-2 - 2) ??

13. texaschic101

almost...pay close attention to your numbers and signs (-4,3) and (-2, -6) slope = (-6 - 3) / (-2 -(-4)

14. texaschic101

so for A.. slope = (-6 - 3) / (-2 - (-4) slope = -9/ (-2 + 4) slope = -9/2........we need a slope of -3/2,,,so this is not correct

15. anonymous

so -6 - 3 = -9 -2 - -4 = 2 m = -9/2

16. texaschic101

that is the slope of those points...but we need a slope of -3/2...so thats not it

17. anonymous

We were thinking the same thing lol. Anyway so for Answer B. (6 - (-3) / (2 - (-4) 6 - -3 = 9 2 - -4 = 6 9/6 so that one is incorrect too

18. texaschic101

(-4,-3) / (2,6) slope is 9/6...but that reduces...what does that reduce to ?

19. anonymous

3/2 or 1 1/2

20. texaschic101

it reduces to 3/2...but we need -3/2....so this is not correct

21. texaschic101

22. anonymous

C. (-6 - 3) / (2 - (-4) -6 - 3 = -9 2 - -4 = 6 -9/6 reduce -3/2

23. anonymous

So C is correct ?

24. texaschic101

(-4,3) / (2,-6) ... (-6 - 3) / (2 - (-4) -9/6 reduces to -3/2......yep...you got it...WAY TO GO giving you a medal..you deserve it :)

25. anonymous

Thanks for the help ^^

26. texaschic101

anytime...as long as its not geometry...not so good at that :)

27. anonymous

I'm pretty good in geometry XD It's algebra I suck at

28. texaschic101

I am kinda the opposite....can handle algebra pretty well...just know about the basics in geometry