1.
a- (b-(c-(d-x))) = e
a-(b-(c-d+c+x)) = e
a-(b-c+d-x) = e
a-b+c-d+x = e
x = e/ a+b-c+d
2.
V1= 1*1*1 = 1 cm3
V2= 2*2*2 = 8 cm3
1 cm3 19g
8cm3 x
x= 19*8= 152g
+
