## anonymous one year ago Tabitha is trying to find the equation of a line perpendicular to y = 1 over 2x − 5 in slope-intercept form that passes through the point (2, −7). Which of the following equations will she use?

1. anonymous

a) y − (−7) = 1 over 2(x − 2) b) y − 2 = 1 over 2(x − (−7)) c) y − (−7) = −2(x − 2) d) y − 2 = −2(x − (−7))

2. anonymous

@satellite73

3. anonymous

you been at this one for a while huh?

4. anonymous

yes! can't seem to figure it out :(

5. anonymous

ok lets go slow (but not that slow) the slope of $y=\color{red}{\frac{1}{2}}x-5$ is ?

6. anonymous

hint: it is red

7. anonymous

1/2

8. anonymous

right and the perpendicular line with have a slope that is the "negative reciprocal" i.e. flip it and change the sign

9. anonymous

2/1?

10. anonymous

-2/1*

11. anonymous

right, which, on planet earth, we usually just call $$-2$$

12. anonymous

haha right

13. anonymous

now we got the slope the point is $$(2,-7)$$ and they want you to plug all this in to the "point - slope" formula $y-y_1=m(x-x_1)$

14. anonymous

where you see $$y_1$$ put $$-7$$ where you see $$m$$ put $$-2$$ and where you see $$x_1$$ put $$2$$

15. anonymous

so would it be c?

16. anonymous

yes, it is always C how hard was that? ok?

17. anonymous

thank you so much!