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If 

\(\begin{cases} a+b=17 \\ c+d=20 \\ a-d = \frac{d-c}2 = 1 \end{cases}\)

 

find (b + c)/(a - b).

 Jun 18, 2020
 #1
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First off, we substitude a=17-b

 

c+d=20

17-b-d=1

17-b-d=(d-c)/2

 

Then we substitude c=20-d

 

17-b-d=1

17-b-d=(d-[20-d])/2

 

Substitude

 

17-(-d+16)-d=(d-[20-d])/2

 

Which, when simplified and drawn out gives us d=11

 

Substitude b=-d+16

 

B=5

 

Plug it into C=20-d

 

c=20-11

 

c=9

 

Add it to a=17-b

 

a=17-5

 

a=12

 

So we get to our last equation:(5+9)/(12-5)

 

14/7

 

14/7=2

 

Yay!

 Jun 18, 2020

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