1 )If a + b + c = 0 ( a2 / bc ) + ( b2/ ca ) + ( c2 / ab ) = 3

2 ) Find the value of a ) 553 - 253 - 303

b ) 993

1) a  + b + c = 0

(a2 / bc) + (b2 / ca) + (c2 / ab)

=( a3 + b3 + c3 ) / abc

If a + b + c = 0 , then a3 + b3 + c3 = 3abc

3abc / abc = 3

2) (55)3 + (-25)3 + (-30)3

a = 55 , b = - 25 , c = -30

a + b + c = 55 - 25 - 30 = 0

If a+ b + c = 0 then a3 + b3 + c3 = 3abc

Answer: 3 * 55 * ( - 25) * ( - 30)

= 123750.

3) (99)3

= (100 - 1)3

(100)3 - 13 - 3*100 * 1(99)

1000000 - 1 - 29700

= 970299

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