Question

Stiind ca 2b+3c=10 si 6a+5b+4c=32
Stim si ca b+c = 4

VA ROG AJUTATI-MA!!!!!!

Answer 1

2b  +  3c   = 10 
3b  + 3c = 4 · 3 
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scazute  2b  + 3c   - 3b  - 3c = 10 - 12   
                   - b = - 2             ⇒  b = 2 
si  c = 4 -b = 4 - 2 = 2                c =2

6a  + 5 · 2 + 4 ·2 = 32     
6a  + 10 + 8  =32 
6a = 32 - 10 - 8 = 14 
6a = 14          ; a = 14 /6 = 7 / 3

Answer 2

$2b+3c=10 \\ 6a+5b+4c=32 \\ b+c=4 \Rightarrow b=4-c \\ 2b+3c=10 \Rightarrow 2(4-c)+3c=10 \Rightarrow 8-2c+3c=10 \Rightarrow \\ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~\Rightarrow-2c+3c=10-8 \Rightarrow \boxed{c=2}$
$\displaystyle b=4-c \Rightarrow b=4-2 \Rightarrow \boxed{b=2} \\ 6a+5b+4c=32 \Rightarrow 6a+5 \cdot 2+4 \cdot 2=32 \Rightarrow 6a+10+8=32 \Rightarrow \\ ~~~~~~~~~~~~~~~~~~~~ \Rightarrow 6a=32-10-8 \Rightarrow 6a=14 \Rightarrow a= \frac{14}{6} ^{(2} \Rightarrow \boxed{a= \frac{7}{3}}$