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

by RoRi

June 29, 2015

Prove that $(a-b) + (b-c) = (a-c)$ .

Proof. From Theorem I.3 we know $a-b = a+(-b)$ , $b-c = b+(-c)$ and $(a-c) = a+(-c)$ . So,

$(a-b) + (b-c) &= a+(-b) + b + (-c) = a + (-c) = a-c. \qquad \blacksquare$

Stumbling Robot