Question

Use the quadratic formula to find any x-intercepts on the graph of the equation. y=4x^2+8x-6

Answer 1

this is what I have already got so far before I get stuck

Answer 2

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

Answer 3

a=4
b=8
c=-6

Answer 4

\[x=\frac{ -8\pm \sqrt{8^{2}-4\times4\times(-6)} }{ 2\times4 }\]

Answer 5

\[x=\frac{ -8\pm \sqrt{64+96} }{8 }\]

Answer 6

\[x=\frac{ -8\pm \sqrt{160} }{ 8 }\]

Answer 7

The I am stuck

Answer 8

We have to simplify the radical, so what are some factors of 160?

Answer 9

To make it easier you can use 4*4*10=160 or 4^2*10=160

Answer 10

1x160 2x80 4x40 5x24 6x20 8x15 10x12

Answer 11

\[x=\frac{-8\pm 4\sqrt{10} }{ 8}\]

Answer 12

Do you see how I got that?

Answer 13

no

Answer 14

Okay, One of the factors for 160 is 16*10
We know that the square root of 16 is four, therefore we can remove a four from under the radical, leaving the ten behind.

Answer 15

Make more sense?

Answer 16

yes and now I see it because I messed up and was factoring 120 instead of 160

Answer 17

No problem. You know what to do next?

Answer 18

it would make your work easier by a factor of two if you started with
\[2x^2+4x-3=0\] and then used the quadratic formula

Answer 19

@satellite73 You wanna help them? I don't want to confuse them by contradicting you? :c

Answer 20

no you go ahead

Answer 21

I now simplify by factoring out a common factor of 4 from the numerator and cancelling it out with a factor of 4 in the denominator

Answer 22

Perfect, so what do you have left?

Answer 23

\[x=\frac{ -2+\sqrt{10} }{2 }\]

Answer 24

\[x=\frac{ -2-\sqrt{10} }{ 2 }\]

Answer 25

Okay so now your x intercepts are \[(\frac{ -2+ \sqrt{10}}{2 },0) and (\frac{ -2- \sqrt{10}}{2 }, 0)\] Unless you're allowed to use a calculator then you can simplify this c:

Answer 26

ok thanks for helping me.

Answer 27

No prob c: you already had it

Answer 28

i got stuck at the factoring but i see where i was messing up at