+0  
 
0
210
2
avatar

Let line $l_1$ be the graph of $5x + 8y = -9$. Line $l_2$ is perpendicular to line $l_1$ and passes through the point $(10,10)$. If line $l_2$ is the graph of the equation $y=mx +b$, then find $m+b$.

 Apr 11, 2019
 #1
avatar+25824 
+1

5x+8y= -9     re-arrange in to   y= mx + b form

 

8y = -5x - 9

y = -5/8 x - 9/8       shows m1  (the slope) = =5/8

 

Remember how to find pepindicular slope?

 

- 1 / m1   will be perpindicular      -1 / (-5/8)  = 8/5

so the line we are looking for is   y = 8/5 x + b      Now sub in the point given (10,10) to find the value of b

                                                   10 = 8/5 (10) + b      b = -6

 

your line is       y = 8/5 x - 6        m+ b = 8/5-6 = - 4 2/5

 Apr 11, 2019
edited by ElectricPavlov  Apr 11, 2019
 #2
avatar+25824 
+1

Here is a pic:

 Apr 11, 2019

25 Online Users

avatar
avatar
avatar
avatar
avatar
avatar
avatar