At a used book sale,5 books cost $15. How many books can u buy for $21

7 books

Step-by-step explanation:

first divide 15 and 5 = 3 dollars per book

then divide 21 and 3 = 7

So you can buy 7 books with 21 dollars

answer:

the position of equilibrium will shift to the left.

step-by-step explanation:

the general equation for the dissociation of a weak base is

b + h₂o   ⇌   bh⁺ + oh⁻

according to le châtelier's principle, when a stress is applied to a system at equilibrium, the system will respond in a way that tends to relieve the stress.

if you apply a stress by adding more bh⁺ or oh⁻,   the system will respond by moving in a direction that gets rid of the added ions.

the position of equilibrium will shift to the left, forming more of the undissociated base.