Inequalities Question?

[super_chris1234]

Hi all,

I really appreciate all the help people are giving on this website.

I'm still preparing for an aptitude test and am now reviewing inequalities. I have a question about inequalities I'm not to sure of

5x²+9<2x+6

How would I get started in here? Set the inequality to equal zero?

Also, does anyone have any strategies on taking tests?

Thanks,

Chris

 

[galactus]

Yes, you can set it equal to 0 by writing it as \(\displaystyle 5x^{2}-2x+3<0\)

But, notice something about this one?.

\(\displaystyle 5x^{2}-2x+3>0, \;\ \forall x\)

In other words, your inequality is false for all x. There is no value of x that satisfies the inequality.

If you graph your inequality, you will see the parabola never crosses the x-axis. Its roots are complex.

In other words, it can never be less than 0.