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
146
2
avatar

A line passes through (4,365), and the y-intercept of the line is on or between 1 and 9 . What is the minimum possible slope of the line?

 Jul 9, 2019
 #1
avatar+8759 
+5

Let the y-intercept be the point  (0, a)  where  1 ≤ a ≤ 9

 

So the slope   =   \(\frac{\text{rise}}{\text{run}}\ =\ \frac{365-a}{4-0}\ =\ \frac{365-a}{4}\)

 

To make the slope as small as possible, we want to make the fraction  \(\frac{365-a}{4}\)  as small as possible.

 

To make the fraction as small as possible, we want to make the numerator as small as possible (we can't change the denominator).

 

And to make the numerator as small as possible, we want to subtract as much as we can from  365 .

 

To make  365 - a  as small as possible, we want to make  a  as large as possible.

 

The largest possible value of  a  is  9 ,  so the smallest possible value of the numerator is  365 - 9

 

And the smallest possible slope  =  \(\frac{365-9}{4}\ =\ \frac{356}{4}\ =\ 89\)

 

It's kind of hard to see the difference but here is a graph where you can see what changing the value of  a  does to the slope:

https://www.desmos.com/calculator/n0tbxct0al 

 Jul 9, 2019
 #2
avatar+103999 
+2

The minimum slope occurs when the y intercept is (0,9)

 

And the slope is

 

[ 365 - 9 ]           356

________  =     ____  =      89

 [ 4 - 0 ]                4

 

 

cool cool cool

 Jul 9, 2019

33 Online Users