y = −8x^4 + 18x + 900 End behavior: y →? as x → ∞, y →? as x → −∞

Question

Need help finding the end behavior.

Answer 1

Look at edges of graph:   https://www.desmos.com/calculator/zbxsngtgdo

 

I scaled it back so it would fit on the graph, but where is y headed at the left edge?  Where is y headed at the right edge?

 

So

As x→–∞, y→–∞

As x→+∞, y→–∞

Answer 2

y---> - infinity as x--> infinity

 

y--->- infinity as x--> -infinity  <--- the degree of power 4 makes the negative number positive,....

 

               (negative)^4 = positive