Question

If a +b +c=-1 and ab +bc+ Canada=-4 then find the value of a ^2+b^2 +c^2.

Answer 1

Hi ,

It is given that ,

a + b + c = -1 ----( 1 )

ab + bc + ca = - 4 ---( 2 )

Do the square of equation ( 1 ) , we get

( a + b + c )² = ( -1 )²

a² + b² + c² + 2( ab + bc + ca ) = 1

a² + b² + c² + 2 ( - 4 ) = 1

a² + b² + c² - 8 = 1

a² + b² + c² = 1 + 8 = 9

I hope this helps you.

: )

Answer 2

a + b + c = -1

Square on both sides,

(a+ b + c)² = (-1)²

a²+b²+c²+2(ab+bc+ca) = 1

a²+b²+c²+2(-4)=1

a² + b²+ c² -8 = 1

a²+b²+c²= 1+8

a²+b²+c² = 9

I hope this will help you

-by ABHAY