If a^2 + b^2 + c^2 = 2a-2b - 2, then the value of 3a - 2b + c is

SSC CHSL Model Paper 5

Question : 44 of 100

Marks: +1, -0

a^2 + b^2 + c^2 = 2a-2b - 2

, then the value of

3a - 2b + c

Solution:

a^2 + b^2 + c^2 = 2a-2b - 2

(a^2- 2 a+ 1) + (b^2 + 2b +1) + c^2 = 0

( a - 1)^2 + (b +1 )^2 +c^ 2= 0

This equation is possible if
a - 1 = 0 , b + 1 = 0 and c = 0
a = 1, b = -1, c = 0

3 a -2 b + c= 3 × 1 -2 × (-1 ) + 0

= 3 + 2 = 5

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