Question

Solve for x in x2 + 16x + 9 = 0

Answer 1

You've heard of the quadratic formula correct?

Answer 2

@johnweldon1993

Answer 3

\[\frac{ -b+/- \sqrt{b^2-4ac} }{ 2a}\]

Answer 4

Yes as @Luigi0210 has shown ...What you have shown...that is the FORM of a quadratic

The quadratic formula is the

\[\frac{ -b \pm \sqrt{b^2 - 4ac} }{ 2a }\]

Answer 5

You have an equation

x2 + 16x + 9 = 0

With 3 coefficients

1x² + 16x + 9

1 is your FIRST coefficient...so assign that value to the letter 'a'
16 is your SECOND coefficient...so assign that value to the letter 'b'
and
9 is your THIRD coefficient...so assign that to the letter 'c'

So what will your equation look like?

Answer 6

-16±√16^2-4(1)(9)/ 2(1) @johnweldon1993

Answer 7

@Luigi0210 ?

Answer 8

\[\frac{ -16 \pm \sqrt{16^{2}-4(1)(9)} }{ 2(1) }\]
\[\frac{ -16 \pm \sqrt{256-36} }{ }\]
\[\frac{ -16 \pm \sqrt{220} }{ 2 }\]

Answer 9

Good job @CSmith17 , now what you will have is two equations, (-16/2)+ (radical/2) and (-16/2)-(radical/2), from that you will get your two roots for this problem.

Answer 10

@RoseDryer is that final?

Answer 11

it is not final....you should equate those 2 equations that you will now have

\[\frac{ -16 + \sqrt{220} }{ 2 }\]
and
\[\frac{ -16 - \sqrt{220} }{ 2 }\]

solve those to get a number and those will be your answers to 'x'

Answer 12

So i got -0.5 and -15.5 @johnweldon1993

Answer 13

Use Quad.Equation

Answer 14

probably keep more decimal places and round only at the end...

so it'd be - .058 and -15.4 that I get

Answer 15

So -.058 and -15.4 would be the final answer? Or only one of them? @johnweldon1993

Answer 16

Both would be a correct answer for 'x' try it...try plugging both answers in for 'x' in your equation and you will get 0 (probably not EXACTLY because we DID round) but yes