Questions related to Quadratics

[ashwinkandel]

Find the range of value of c, given that, for all values of x, x^2+5x+c>2

[........]

c>33/4

[ashwinkandel]

Can you show me the process?? how did u take out the answer

[astarmathsandphysics]

Complet the squuare
x^2+5x+c>2
(x+2.5)^2-2.5^2+c>2
(x+2.5)^2-2.5^2+c-2>0
(x+2.5)^2 is a square number so must be greater than zero, so
-2.5^2+c-2>0 so c>2.5^2+2=8.25

[ashwinkandel]

I am little bit confused with the last steps of the solution:
(x+2.5)^2 is a square number so must be greater than zero, so
-2.5^2+c-2>0 so c>2.5^2+2=8.25
I accept that (x+2.5)^2 is always greater than zero, then how can we say that -2.5^2+c-2 is also greater than zero?

[ashwinkandel]

Can you also give a glance to this question:

[astarmathsandphysics]

Do you mean the question in black written in the black rectangle?

[astarmathsandphysics]

Because if (x+2.5)^2>0 sub (x+2.5)^2=00 into (x+2.5)^2-6.25+2-2>0 then solve for c

[ashwinkandel]

Thanks for clarification and yes, i mean the question in the  black rectangle

[astarmathsandphysics]

I can't read it.

[ashwinkandel]

Right click the image and click view image or just go to http://i53.tinypic.com/16gk02t.png

[astarmathsandphysics]

A is 3 b is 2
Is there a diagram or min or max value of the function

[ashwinkandel]

Max. Value of the function is given in the next part and diagram is asked to be drawn. I am still confused how you took out the value of a as 3.