Question

$(a + b) + c = a + (b + c) a = \frac{1}{3} b = \frac{2}{5} c = \frac{ - 3}{7}$
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Answer 1

Answer:

a = 27/14 ; b = -9/7 ; c = -15/14.

EXPLANATION:

From the question we observe that,

1/3 * b = -3/7

b/3 = -3/7

After cross multiplication we get,

7b = -9

b = -9/7

And in the same way,

2/5 * c = -3/7

2c/5 = -3/7

14c = - 15

c = -15/14

Now , substitute the values of a and c in

(a+b)+c = -3/7

$(a + \frac{ (- 9)}{7} ) + \frac{ (- 15)}{14} = \frac{ - 3}{7} \\ \\ ( \frac{7a - 9}{7} ) - \frac{15}{14} = \frac{ - 3}{7} \\ \\ \frac{2(7a - 9) - 15}{14} = \frac{ - 3}{7} \\ \\ \frac{14a - 18 - 15}{14} = \frac{ - 3}{7} \\ \\ \frac{14a - 33}{14} = \frac{ - 3}{7}$

After cross multiplication we get,

$7(14a - 33) = ( - 3)(14) \\ \\ 14a - 33 = \frac{ - 42}{7} \\ \\ 14a - 33 = - 6 \\ \\ 14a = - 6 + 33 \\ \\ 14a = 27 \\ \\ a = \frac{27}{14}$

Hence, a = 27/14 ; b = -9/7 ; c = -15/14.