Question

solve 2x^2+9x=−5 using the quadratic formula, round to the nearest hundred if more then one answer separate with commas.

Answer 1

@hero

Answer 2

Well first...you need to set this equal to 0...so add 5 to both sides of the equation

Answer 3

2,9,-5?

Answer 4

5+2X^2+9X=-5+5 Like that?

Answer 5

Yes, just remember to order it correctly afterwards, So you would have

\[\large 2x^2 + 9x + 5 = 0\]

NOW what are your 'a' 'b' and 'c' ?

Answer 6

a=2 b=9 c=5

Answer 7

Perfect! *just remember the equation always need to be = 0"

So we have

a = 2
b= 9
c = 5

The quadratic formula says

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

So when we plug in all the numbers we have?

Answer 8

-9+sqrt(9^2-4(2)(5)/2(2)

Answer 9

\[-9+\sqrt{9^2-4(2)(5)}/2(2)\]

Answer 10

Mmhmm

\[\large \frac{-9 \pm \sqrt{9^2 - 4(2)(5)}}{2(2)}\]

so we simplify a little to

\[\large \frac{-9 \pm \sqrt{81 - 40}}{4}\]

what does the square root simplify to?

Answer 11

\[\sqrt{41}\]

Answer 12

Right, so now we break it into our 2 equations

\(\large \frac{-9 + \sqrt{41}}{4}\) and \(\large \frac{-9 - \sqrt{41}}{4}\)

and just solve those 2...those are your 2 values

Answer 13

does it go into a decimal?

Answer 14

it will go into a decimal yes...unless you're supposed to keep it exact in which case this will be done

Answer 15

i need to round it to the nearest hundred

Answer 16

Ahh, then there you go, so evaluate the decimals and round to the nearest hundredth...and then you're all set :)

Answer 17

1.−0.64921894

2.−3.85078105

idk how to round to the nearest hundred :(

Answer 18

That's okay

Just remember



that's the first one...so rounded to the nearest hundredth would be -0.65 right?