Question

How would you solve 4x^2 – 6x – 10 = 0?

Answer 1

You can factor it or use the quadratic formula.

Answer 2

this can be factored

Answer 3

How would the quadratic formula be used?

Answer 4

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

Answer 5

\[
ax^2+bx+c
\]

Answer 6

Isnt 4x^2-6x-10 already in ax^2+bx+c form?

Answer 7

Yes, so plug in the coeffecients into the quadratic formula and you'll get the solutions.

Answer 8

so itd be x=-6+- sqrt 6^2-4*4810/2*4?

Answer 9

You can't drop the negative signs.\[
a=4, b=-6, c=-10
\]

Answer 10

okay so x=-6+-sqrt-6^2-4*4*-10/2*4?

Answer 11

Yeah.

Answer 12

can you help me simplify that my calculator is being stupid...and isnt wanting to do sqrt or exponents.,../:

Answer 13

Remember the order of operations. Do it one operation at a time.

Answer 14

^ you should probably use some parentheses when you write math like that. It's almost impossible to read.

Note you can divide both sides of the equation by 2 first
\[4x^2 – 6x – 10 = 0 \] after dividing it all by 2 becomes \[\large 2x^2 - 3x -5 = 0\] and this can be factored, you don't need the quadratic formula.

Answer 15

@agent0smith I need it in quadratic formula thats what the teacher said

Answer 16

Is -6+-sqrt36- -160/8 correct? @wio

Answer 17

Okay, then you just need to plug it all in. Just make sure you use order of operations correctly... I'm guessing by the way you typed it, that you did not. You can not enter it that way into a calculator. Use parentheses.

Answer 18

where would i put parentheses?...ugh i hate math...

Answer 19

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

\[x = \frac{\left( 6 \pm \sqrt{\left( 6^2 - 4*4*(-10) \right)} \right)} {2*4}\]

Answer 20

so first you do (-6^2-4*4*(-10))? then multiply that by -6 then divide that by 2*4?

Answer 21

first you do (-6^2-4*4*(-10))? yes.

then multiply that by -6 ... no, there's no multiplication by -6.

Answer 22

then what would you do?

Answer 23

First simplify everything under the square root.

Answer 24

-6^2=36 4*4*-10=-160 so sqrt36- -160?

Answer 25

Yes, now simplify the 36-(-160)

Answer 26

Would you multiply that or add it since its a - -?

Answer 27

Add it

Answer 28

Two negatives make a positive.

Answer 29

so 36+160=196?

Answer 30

Correct. So now it's \[x = \frac{\left( 6 \pm \sqrt{196} \right)} {2*4}\]

Answer 31

Then would you multiply 2*4? and I still dont understand what to do with the -6+- thing.

Answer 32

The +- means plus OR minus. It really means: \[x = \frac{\left( 6 +\sqrt{196} \right)} {2*4}\] or \[x = \frac{\left( 6 - \sqrt{196} \right)} {2*4}\]

But yes, multiply the 2 by 4.

Answer 33

Or take the square root of 196.

Answer 34

so then x=(-6+sqrt196)/8.

Answer 35

Close, but you shouldn't have a negative 6 there, since it should be -b, which is -(-6).

Answer 36

and don't forget x=(6+sqrt196)/8 OR x=(6-sqrt196)/8.

Answer 37

so itd turn into a positive 6? and the sqrt196 is 14,right?

Answer 38

Correct. Now you have x=(6+14)/8 or x=(6-14)/8

Answer 39

do I solve both x=(6+14)/8 and x=(6-14)/8?

Answer 40

Correct.

Answer 41

Thanks so much! :)

Answer 42

No prob :) did you get the two solutions for x?

Answer 43

I got 2.5=(6+14)/8 and -1=(6-14)/8

Answer 44

Correct :)

Answer 45

So x = 2.5 and x=-1

Answer 46

Yes I got that! :)) Thanks again