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# Geometry question and inequality

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1. Let line L1 be the graph of 5x+8y=-9 . Line L2 is perpendicular to line L1 and passes through the point (10,10) . If line L2 is the graph of the equation Y=mX+b , then find m+b
2. I have a large truck and my neighbor has four identical small trucks. My truck can carry at least 800 pounds more than each of her trucks, but no more than one-third what all four of her trucks combined can carry. Knowing only these facts, what is the largest number of pounds that I can be assured of being able to carry in my truck?

Please show work because I am confused on how to do this.

Aug 26, 2018
edited by thunderkirby  Aug 26, 2018

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First one answered here : https://web2.0calc.com/questions/help_9075

Aug 26, 2018
edited by CPhill  Aug 26, 2018
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Oh okay XD i can't seem to find this stuff :P

Aug 26, 2018
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Here's the way I interpret the second question

Let your truck be capable  of carrying  x  lbs

Let  the total number of pounds that your neighbor can carry in 4 identical trucks  =  y

So each of your neighbor's trucks can carry  y / 4   lbs

"My truck can carry at least 800 pounds more than each of her trucks"  translates to

x ≥  800 + y / 4

And

"...but no more than one-third what all four of her trucks combined can carry"  translates to

x ≤  y/3

Look at the intersection point of these two inequalities :  https://www.desmos.com/calculator/xggshl0aos

Your truck can carry  3200 lbs  .....

Your neighbor's trucks can carry  9600 lbs

So  each of her trucks  can carry  9600/ 4  = 2400 lbs

And your truck carries at least 800 lbs more than each of her trucks [ 3200 - 2400 ]

Plus  your truck can carry no more than 1/3  of what all 4 of her trucks can carry.....9600/3  = 3200 lbs

Aug 26, 2018
edited by CPhill  Aug 26, 2018
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Oh wow! I never thought of it as an intersection question! That helps alot! oh Im acidentally using a guest...

Aug 26, 2018