A few days ago

Anonymous

algebra please help?

how do u go about this?

m^2+m+1=0

My work:

m^2+m=-1

m(m+m)=-1

m(2m)=-1

m=-1 m=-1/2

but i am suppose to get m=-1/2 plusminus (radical 3/2)i

thanks

Top 2 Answers

A few days ago

Favorite Answer

so the question asks for the value of m.

you can either use quadratic formula or solve by completing the square.

i prefer the second method. (completing the square)

m^2 + m + 1 = 0

subtract 1 for both sides

m^2 + m = -1

since the leading coefficient is already 1, add (b/2)^2 for both sides

m^2 + m + (1/2)^2 = -1 + (1/2)^2

simplify

m^2 + m + 1/4 = -3/4

factor

(m + 1/2)^2 = -3/4

take a square root

m + 1/2 = sqrt(-3/4)

m + 1/2 = +/- sqrt ( -1 * 3/4)

m + 1/2 = +/- sqrt(-1) * sqrt(3/4)

we know that sqrt(-1) = i

m + 1/2 = +/-sqrt(3/4)i

now subtract 1/2 for both sides

m = -1/2 +/- sqrt(3/4)i

or m = -1/2 +/- sqrt(3)i/2

A few days ago

Anonymous

Your second step doesn’t work…

m(m+m) = m^2 + m^2…

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