How much smaller is 15x-18y+19z than 22x-20y-13z+26?
The required result is (22x-20y-13z+26)-(15x-18y+19z)
=22x-20y-13z+26-15x+18y-19z
=7x-2y-32z+26
Question 99(ii)
(−2)3×(−2)6=(−2)2x−1