First slide

Theory of equations

Question

The expression $x^{2} + 2 bx + c$ has the positive value if

Moderate

A

$b^{2} - 4 c > 0$
B

$b^{2} - 4 c < 0$
C

$c^{2} < b$
D

$b^{2} < c$

Solution

$x^{2} + 2 bx + c = {(x + b)}^{2} + c - b^{2}$
$∵ {(x + b)}^{2}$ is a perfect square, there fore the given expression is positive if $c - b^{2} > 0 or b^{2} < c .$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App