please guys help me solve this question
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hope this helps u :-)
Step-by-step explanation:
(3a + 2b + 7c) = 2
it is given that, a² + 4b² + 49c² + 18 = 2(2b + 28c - a)
⇒a² + 4b² + 49c² + 18 = 4b + 56c - 2a
⇒a² + 2a + 4b² - 4b + 49c² - 56c + 18 = 0
⇒a² + 2a + 1 + 4b² - 4b + 1 + 49c² - 56c + 16 = 0
[ use formula, a² - 2ab + b² = (a - b)² ]
⇒(a + 1)² + (2b - 1)² + (7c - 4)² = 0
⇒a = -1, b = 1/2 , c = 4/7
then, (3a + 2b + 7c)
= 3 × -1 + 2 × 1/2 + 7 × 4/7
= -3 + 1 + 4
= 2
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