## Diana97 3 years ago f point C is the midpoint of /AB , what is the coordinate of point B? (–9, 2) (–3, 1) (0, –7) (–1, –8)

1. Diana97

2. panlac01

mid-point again LOL

3. panlac01

read pages 2 and on - http://finedrafts.com/files/Larson%20PreCal%208th/Larson%20Precal%20CH1.pdf

4. panlac01

mid-point formula is in page 5

5. Diana97

so is A

6. Diana97

plz is it

7. panlac01

8. Diana97

yes

9. Diana97

bout c

10. waterineyes

$\large Midpoint(x,y) = (\frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2})$ Here: $$(x,y) = (-3, -5)$$ , $$(x_1, y_1) = (-6, -3)$$ and we have to find $$x_2$$ and $$y_2$$ $\large Midpoint(-3,-5) = (\frac{-6 + x_2}{2}, \frac{-3 + y_2}{2})$ Try to equate x coordinate of Left side with the right side.. Similary do for y coordinates on both the sides.. and find $$x_2$$ and $$y_2$$...

11. Diana97

ok so is should be A or c

12. panlac01

for x, what do you need to add to -6 so when you divide it by 2, you get -3? the same technique for y.

13. waterineyes

Simply solve this: $\frac{-6 + x_2}{2} = -3$ Multiply 2 both the sides and then add 6 both the sides and tell me what are you getting for $$x_2$$..

14. panlac01

D, [-6+(-9)]/2 = -3?

15. waterineyes

What is this @panlac01

16. panlac01

17. panlac01

indirectly, of course

18. panlac01

when you get a chance, Diana, please review http://www.purplemath.com/modules/negative.htm

19. Diana97

ok Thinks