Question

Use the quadratic formula to find the roots of the equation. x2 + 3x - 18 = 0
A.{-6, 3}
B.{-2, 9}
C.{-3, 6}
D.{-9, 2}

Answer 1

quadratic formula is
\[x=(-b \pm \sqrt{b^2-4ac})/(2a)\]
Put a=1, b=3 and c=-18 to the formula and see what you can get :)

Answer 2

A.

http://www.wolframalpha.com/input/?i=solve+x2+%2B+3+x+-+18+%3D+0+&t=sftb01

Answer 3

\[x=(-3 \pm \sqrt{3^2-4(1)(-18)})/(2(2))\]

Answer 4

thank you :)