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FASSSTTTTTt

FunMath  Dec 13, 2017
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2+0 Answers

 #1
avatar+81022 
+1

Here's 1

 

We have  the following two functions :

y =  12x  + 50

y  =  20x

 

Here's the graphs :  https://www.desmos.com/calculator/9quniellja

 

The break-even point is at  ≈  7 cars

 

This means  that if he sells 7 cars or more, he makes a profit

 

 

cool cool cool

CPhill  Dec 14, 2017
 #2
avatar+81022 
+1

The idea in the first two is to multiply through by the common denominator of both fractions

 

2.  (1/2)x + (3/2)y  = 4   multiply through by 2 ⇒  1x  + 3y   = 8

     (2/3)x  - (1/3)y  = 7  multiply through by 3  ⇒  2x -   1y   = 21

 

3.  (-1/3)x  + (1/2)y  = 5   multiply through by 6 ⇒  -2x  + 3y  = 30

     (3/4)x  -  (1/4)y  = 10  multiply through by 4  ⇒  3x  - 1y  = 40

 

4.  .5x + 1.2 y  = 2   multiply  through by 10   ⇒  5x  + 12y  = 20

     3.3x - .7y =  3     multiply through by 10   ⇒  33x  - 7y  =  30

 

 

 

cool cool cool

CPhill  Dec 14, 2017

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