Respuesta :

akaleti47
c=2b
d=c+7
b+c=57⇒b+2b=57⇒3b=57⇒ b=19, c=2*19=38, d=38+7=45
thats given

lets find if there is an x such that  d-x=b+x=c⇔ 43-x=19+x=38
43-x=38⇒x=43-38=5
19+x=38⇒x=19
there is no single x (cant be both 5 and 19)
so, i think dan was incorrect.