Question

(b+c)²-b(b-2c)

b= -2
c=3,5

Answer 1

b²+2bc+c²-b²+2bc=4bc+c²=4*-2*3.5+12.25=-15.75

Answer 2

1) ( b + c ) ^ 2 = b^2 + 2bc + c^2 ;
2) - b * ( b - 2c ) = - b^2 + 2bc
3) b^2 + 2bc + c^2 - b^2 + 2bc = 4bc + c^2 = c * ( 4b + c )
4) b = - 2 , c = 3,5
3,5 * ( 4 * ( - 2 ) + 3,5 ) = 3,5 * ( - 8 + 3,5 ) = 3,5 * ( - 4,5 ) = - 15,75