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The sum of the roots of 2x2 + 8x - 3 = 0 Is

User Panzi
by
4.9k points

2 Answers

0 votes

Answer:

Find the roots of

2

x

2

+

8

x

3

=

0

by solving for

x

.

Exact Form:

x

=

4

±

22

2

Decimal Form:

x

=

0.34520787

,

4.34520787

Explanation:

I have used an Algebra calculator to check my answer given and my answer is correct.

User Gurjit Singh
by
4.6k points
0 votes

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2 {x}^(2) + 8x - 3 = 0


(x - ( ( - 8 + √(88) )/(4) ) \: )(x - ( ( - 8 - √(88) )/(4) ) \: ) = 0 \\

Thus ;


x - ( ( - 8 + √(88) )/(4) ) = 0 \\


x = ( - 8 + √(88) )/(4) \\

This is one of the roots.

The other root is :


x - ( ( - 8 - √(88) )/(4) ) = 0 \\


x = ( - 8 - √(88) )/(4) \\

So sum of the roots is :


( - 8 + √(88) )/(4) + ( - 8 - √(88) )/(4) = \\


( - 8 - 8 + √(88) - √(88) )/(4) = \\


( - 16)/(4) = - 4 \\

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We have faster way to find ;

Remember from now on ,

If the quadratic functions have two roots ,

Sum of the roots is finding by following equation :


sum \: \: of \: \: the \: roots = - (b)/(a) \\


b = coefficient \: \: of \: \: x


a = coefficient \: \: of \: \: {x}^(2)

So ;


sum \: \: of \: \: the \: \: roots \: = - (8)/(2) \\


sum \: \: of \: \: the \: \: roots = - 4

Done...

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User Hagen Von Eitzen
by
4.3k points