## anonymous one year ago Write the standard form of the equation of the line described. #1) through: (-5,3), perpendicular to y=5/7x+4.

1. anonymous

do you know what the slope of $\huge y=\color{red}{\frac{5}{7}}x+4$ is ?

2. anonymous

5/7

3. anonymous

ok good so the perpendicular line will have slope ?

4. anonymous

5/7

5. anonymous

no, that would be the slope of any parallel line you are asked for a perpendicular line

6. anonymous

what would it be?

7. anonymous

in english (math english) it is the "negative reciprocal" i.e. flip it and change the sign

8. anonymous

-7/5

9. anonymous

right

10. anonymous

now use the point slope formula to find the equation, since you have a point and the slope

11. anonymous

y=-7/5x-5, is this the correct answer?

12. anonymous

i doubt it, since it has all those fractions

13. anonymous

$y-3=-\frac{7}{5}(x+5)$ is a start

14. anonymous

multiply out and get $y-3=-\frac{7}{5}x-7$ oh look the fractions are gone, but now you add $$3$$ to both sides

15. anonymous

y=-7/5x-4

16. anonymous

looks good to me

17. anonymous

My textbook said the answer would be 7x+5y=-20

18. anonymous