B What Are the Sign Rules for Second Degree Functions?

[help]

TL;DR Summary

judge whether the following expressions are larger than, smaller than or equal to zero

judge whether the following expressions are larger than, smaller than or equal to zero
i) a+b+c
ii)a-b+c
iii)4a+2b+c
iv)c-e

I know that <0, b> 0, c> 0, d> 0 and e <0 but I don't know what to do

 

[symbolipoint]

Summary:: judge whether the following expressions are larger than, smaller than or equal to zero

I know that <0, b> 0, c> 0, d> 0 and e <0 but I don't know what to do

inconclusive on most of those.

 

[fresh_42]

Summary:: judge whether the following expressions are larger than, smaller than or equal to zero

judge whether the following expressions are larger than, smaller than or equal to zero
i) a+b+c
ii)a-b+c
iii)4a+2b+c
iv)c-e

I know that <0, b> 0, c> 0, d> 0 and e <0 but I don't know what to doView attachment 263235

Note that e.g. $a+b+c=y(1)$ or $c=y(0)$. Then the equation $y(x)=0$ has two solutions. Which are the solutions in general, and what does it mean that there are two real solutions?

 

[help]

thanks a lot!

 

[mfb]

inconclusive on most of those.

Which one is inconclusive? All of them can be taken from the graph.

 

[symbolipoint]

I was only going by this:

Summary:: judge whether the following expressions are larger than, smaller than or equal to zero

whether the following expressions are larger than, smaller than or equal to zero
i) a+b+c
ii)a-b+c
iii)4a+2b+c
iv)c-e

I know that a<0, b> 0, c> 0, d> 0 and e <0

The "know" part only tells if a number is POSITIVE or NEGATIVE.

Looking at (i),
a+b+c
neg + pos + pos
we do not know how the neg compares to the two pos values.

I see no reason why the graph was shown. It appears to be separate from the given description of O.P. I did not make use of it, so this is my possible misunderstanding.

 

[mfb]

The graph is where OP got the sign information from, but you can get more information from the graph - enough to answer the questions.