618 Worked-Out Solutions to Exercises: Chapters 1 to 9
The first addend in this expression is ready to go! We can use the distributive laws on the
second and third terms to getux+uy+uz+vx+wx+ (v+w)(y+z)The final term can be multiplied out using the product of sums rule from the chapter
text. This gives usux+uy+uz+vx+wx+vy+vz+wy+wzWe can use the commutative law of addition, in its generalized form, to rearrange these
terms so the whole sum is easier to remember:ux+uy+uz+vx+vy+vz+wx+wy+wz