Докажите тождество: (x+y)(x+b)=x^2+(y+b)x+yb

Question

Докажите тождество:
(x+y)(x+b)=x^2+(y+b)x+yb

Answer 1

X^2+bx+yx+yb=x^2+xy+bx+yb

Answer 2

X^2 + ( Y + B )*X + YB = X^2 + XY + XB + YB 
( X + Y)*( X + B ) = X^2 + XB + XY + YB