Area of rectangle is given by:
This is the concept of algebra:
Area=length*width
thus:
rewrite the above for length we get:
length=(Area)/(width)
given that:
Area=112a^3b^2
Width=8ab
the length will be:
length=(112a^3b^2)/(8ab)
length=14a^2b
the answer is length=14a^2b units