Question

Determine end behavior? Please help?

Answer 1

its the last one

Answer 2

@GreatMath123 can you explain why

Answer 3

Okay plug in x values in the equation
Start with 1, 10, 100, 300
Then do -1, -10, -100, -300
Observe the behaviour of f(x) for both

Answer 4

Get it's limit at infinity.
\[\lim_{x \rightarrow \infty} -x ^{4}-2x ^{3}+3x+9 = -\infty-\infty+ \infty\]
and it is an unspecified quantity ,so use analysis.
\[\lim_{x \rightarrow \infty} x ^{4}[-1-\frac{ 2 }{ x }+\frac{ 3 }{ x ^{3} }+\frac{ 9 }{x ^{4} }]=\infty ^{4}[-1+0+0+0]=-1*\infty = - \infty\]
\[\lim_{x \rightarrow - \infty} x ^{4}[-1-\frac{ 2 }{ x }+\frac{ 3 }{ x ^{3} }+\frac{ 9 }{x ^{4} }]=(- \infty) ^{4}[-1+0+0+0]=-1*\infty = - \infty\]

Answer 5

If f(x) is increasing when you plug in positive values, it is increasing
If f(x) is decreasing when you plug in positive values, it is decreasing

Answer 6

@Catch.me @orthodoxman so its B?

Answer 7

nope the last one can't you read my post!!

Answer 8

thanks