Answers

  • Brainly User
2015-10-28T17:59:13+05:30
Roots of the equation is given by -b +-√b²-4ac/2a
-(b-c)+√(b-c)²-4(c-a)(a-b)/2(a-b)=-(b-c)-√(b-c)²-4(c-a)(a-b)  both roots are equal
2√{(b-c)²-4(c-a)(a-b)}/2(a-b)=0
squaring both side 
(b-c)²-4(c-a)(a-b)=0
b²+c²-2bc=4(ac-bc-a²-ab)
b²+c²-2bc= 4ac-4bc-4a²-4ab
b²+c²+2bc=4ac-4ab-4a²
(b+c)²=4(ac-ab -a²)       ac=ab because both roots are equal
(b+c)²=-4a²
taking root on both side to make a²  +ve
sp √(b+c)²=√4a²
hence b+c=2a
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