College Math

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r^2+10r-23=0

I used the quadratic formula and I got a -5+2√12

However the real answer is -5+4√3

What am I doing wrong?

  • College Math -

    A survey of 100 people to determine their preferred source of information gave the following results:
    65 watched television
    39 read the newspaper
    39 listened to the radio
    20 watched television and read the newspaper
    27 watched television and listened to the radio
    9 read the newspaper and listened to the radio
    6 watched television, read the newspaper and listened to the radio

    a) How many people surveyed used another means of communication other than the three listed?
    b) How many people surveyed used only one of the three methods of communication?

  • College Math -

    You got the right answer! It just needed to be reduced.
    -5 + 2*ã(12)
    =-5+2*ã(4*3)
    =-5+2*ã4 * ã3
    =-5+2*2*ã3
    =-5+4*ã3

  • College Math -

    My Alt+251 keyboard did not post as a square root--reposting...

  • College Math -

    -5+2*SQR(12)
    =-5+2*SQR(4*3)
    =-5+2*SQR(4)*SQR(3)
    =-5+2*2*SQR(3)
    =-5+4*SQR(3)

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