y-z=155=> z=y-155
x-z=x- (y-155)=x-y+155
x-y=145=> y=x-145
x-y+155=x-(x-145)+155=x-x+145+155=0+145+155=300
deci x-z=300
exercitiul scris pe lung asa vine
x-z=x- (y-155)=x-y+155=x-(x-145)+155=x-x+145+155=0+145+155=300
