Question

quadractic formula: x^2-3x=18? will someone help

Answer 1

You want to get an equation that equals 0, so you subtract 18 for both sides

Answer 2

x^2-3x-18=18-18
x^2-3x-18=0

Answer 3

You can factor this, but do you want to use the quadratic formula?

Answer 4

yes. the quadratic form please

Answer 5

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

Answer 6

We have the quadratic in the form ax^2+bx+c=0

Answer 7

Can you identify a, b, c?

Answer 8

a=1 b=3 c=-18?

Answer 9

a=1, b=-3, c=-18, don't forget your signs

Answer 10

so now we can plug these numbers into the quadratic formula
\[x=\frac{3 \pm \sqrt{(-3)^2-4(1)(-18)}}{2(1)}\]

Answer 11

why is the 3 positive?

Answer 12

\[x=\frac{3 \pm \sqrt{9+72}}{2}=\frac{3 \pm \sqrt{81}}{2}=\frac{3 \pm 9}{2}\]

Answer 13

the 3 is positive because its -b

Answer 14

-(-3)=3

Answer 15

ok. i c now.thank you.

Answer 16

yw

Answer 17

one more question?

Answer 18

sure

Answer 19

i have an imaginary number question... when solving the problem my answer is 3i+6/9. Do I reduce both numbers by 3 resulting answer would be i+2/3

Answer 20

\[\frac{3i+6}{9} or 3i+\frac{6}{9}\]

Answer 21

1st one or second one?

Answer 22

1stt

Answer 23

\[\frac{3(i+2)}{9}\]
Yes, you can reduce to
\[\frac{i+2}{3}\]

Answer 24

okay. thanks

Answer 25

you're welcome