Chapter A.1, Problem 1MP

State the real number property that justifies the indicated statement.

(a) $8+\left(3+y\right)=\left(8+3\right)+y$

(b) $\left(x+y\right)+z=z+\left(x+y\right)$

(c) $\left(a+b\right)\left(x+y\right)=a\left(x+y\right)+b\left(x+y\right)$

(d) $5xy+0=5xy$

(e) If $xy=1,x\ne 0$, then $y=1/x$