Question

How do you solve this equation: 3x2+4x-7=12
that is 3x^2

Answer 1

HI!!`

Answer 2

Hi

Answer 3

start by subtracting \(12\) from both sides to get
\[x^2+4x-19=0\] then use the quadratic formula since this one is not going to factor for you

Answer 4

we have to apply the standard formula, namely:
\[3{x^2} + 4x - 19 = 0\]

Answer 5

oops i meant
\[3x^2+4x-19=0\]

Answer 6

maybe it does factor, who knows?

Answer 7

nope, quadratic formula is what you need
do you know it?

Answer 8

Hmmm. Keep going. I am trying to keep up. (-:

Answer 9

then:
\[\large x = \frac{{ - 2 \pm \sqrt {4 + 57} }}{3} = \frac{{ - 2 \pm \sqrt {61} }}{2}\]

Answer 10

lol i think preetha is just testing the system and checking how QH's work.

Answer 11

solution to
\[ax^2+bx+c=0\] is
\[x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}\]

Answer 12

What do I use for b and a etc?

Answer 13

in your example
\[a=3,b=4,c=-19\]

Answer 14

first step is substitution you get \[x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}\\
x=\frac{-4\pm\sqrt{4^2-4\times 3\times (-19)}}{2\times 3}\]

Answer 15

it is arithmetic from there on in

Answer 16

oops.. I have applied the subsequent formula:
\[\large x = \frac{{ - \left( {b/2} \right) \pm \sqrt {{{\left( {b/2} \right)}^2} - ac} }}{a}\]

Answer 17

Thanks Misty. Thanks Michele. You folks use the equation editor so well. I am embarrassed by my equation. Michele, I will go and rate you help now so you can get the OwlBucks reward.

Answer 18

lol thanks, i need a few more owls

Answer 19

Thanks @Preetha
Thanks @misty1212

Answer 20

Could also complete the square. I like it.

Answer 21

oops.. I have made an error, the right answer is:
\[\large x = \frac{{ - 2 \pm \sqrt {4 + 57} }}{3} = \frac{{ - 2 \pm \sqrt {61} }}{3}\]

Answer 22

Thanks Michele and Misty. You are awesome helpers.

Answer 23

thanks again :) @Preetha

Answer 24

That OR show some algebra skills by completing the square :)

Answer 25

Nincompoop, thanks.

Answer 26

See nincompoop agrees with me. :P