In an answer of at least two well-developed paragraphs, explain how supply and demand work together to reach the equilibrium price in the marketplace.

Market equilibrium happens when supply and demand intersect at one point.

If the price is too high, we will have a surplus. ( that is more objects than needed) If the price is too low we will have a shortage.  ( that is, not many objects to sell)

In either of this situations, the marketplace will work to either raise or lower the price of the object until we get to equilibrium, and the number of those willing and able to buy will be equal to those willing and able to sell.  

i think it is the third one.

question - in 1827, john walker, a druggist in a small english town, tipped a splint with sulphur, chlorate of potash, and sulphid of antimony, and rubbed it on sandpaper, and it burst into flame. the druggist had discovered the first friction-chemical match, the kind we use to-day. it is called friction-chemical because it is made by mixing certain chemicals together and rubbing them. although walker's match did not require the bottle of acid, nevertheless it was not a good one. it could be lighted only by hard rubbing, and it sputtered and threw fire in all directions. in a few years, however, phosphorus was substituted on the tip for antimony, and the change worked wonders. the match could now be lighted with very little rubbing, and it was no longer necessary to have sandpaper upon which to rub it. it would ignite when rubbed on any dry surface, and there was no longer any sputtering. this was the phosphorus match, the match with which we are so familiar. according the paragraph what was the benefit of the new phosphorus match? it burst into flame when rubbed on sandpaper. it was made by mixing chemicals. it could be ignited on any dry surface. it threw fire in all directions.

answer - matches required natural chemicals