A Quadratic simple Doubt From a Brilliant website BLOG

Sir, In the Picture .. Is the QUESTION ....

The roots of x^{2}+4x+5 two Complex number in the form of a±bi. What is the sum of a and b?

The roots of x^{2}+4x+5 is two Complex numbers in the form of a±bi. What is the sum of a and b?

In the Question ... x = -2±i

then $x_{1}$ = -2 + i .................or............... $x_{2}$ = -2 - i

adding both the roots give

$x_{1}$ + $x _{2}$ = - 2 + i - 2 - i = - 4

then the answer to this Question is -4 ., but it is said that the answer is 3

Thank you

Easy Math Editor

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`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
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Comments

Thanks for highlighting the mistakes. I've made some edits, and changed the question.

You are correct in saying that $x_1 , x_2 = -2 + i, -2 - i$ . I forgot about the negative sign in front of $a$ . Note that this gives $a= 2$ and $b=1$ (or possibly -1).

Calvin Lin Staff - 8 years ago

As a native English speaker, I believe the question should be properly worded as, "The roots of x^{2}+4x+5 ARE two Complex numbers in the form of a±bi. What is the sum of a and b?"

Taylor Lau - 8 years ago

yes

thanks

Vamsi Krishna Appili - 8 years ago

Math	Appears as
Remember to wrap math in `\(` ... `\)` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$