We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive pseudonymised information about your use of our website. cookie policy and privacy policy.
 
+0  
 
0
51
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+18279 
+2

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+18279 
+2

Here is a pic:

 Apr 11, 2019

21 Online Users