If 9a^2 + b^2 + 49c^2 + 45 = 2 (6a + 5b - 28c) then the value of 9a + 10b + 28c?

SSC CGL Model Paper 13

Question : 54 of 100

Marks: +1, -0

9a^2 + b^2 + 49c^2 + 45

= 2 (6a + 5b - 28c)

then the value of

9a + 10b + 28c

Solution:

9a^2 + b^2 + 49c^2

+ 45- 2 (6a + 5b - 28c)=0

⇒ 3a = 2 ; a = 2/3

b = 5

7c=-4;c=-4/7

Now,

9a + 10b + 28 c

=9×2/3+10×5

-28×4/7=40

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