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    Hi I'm taking further pure and i have a question about imaginary numbers.
    It would be thankful if you'd helped me

    Verify that 3+i is a root of the quadratic equation

    z^2-(2+4i)z+8i-6=0

    I'm not quite sure if z in the question is just a letter or z=x+iy

    please help me

    thanks
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    (Original post by liemluji)
    Hi I'm taking further pure and i have a question about imaginary numbers.
    It would be thankful if you'd helped me

    Verify that 3+i is a root of the quadratic equation

    z^2-(2+4i)z+8i-6=0

    I'm not quite sure if z in the question is just a letter or z=x+iy

    please help me

    thanks
    z is a variable. It's like me telling you to check whether x=3 is root of the quadratic equation x^2 -8x + 15 = 0. You have two options of doing this, you can either substitute x=3 into the LHS and see that it evaluates to 0 \,, or you could solve the quadratic equation and check that one of the roots is x=3.

    Use this logic here as well. Either plug z  =3+i into your quadratic and see if it evaluates to 0\, or solve it using the quadratic equation and see if one of your roots is indeed 3+i.
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    (Original post by Zacken)
    z is a variable. It's like me telling you to check whether x=3 is root of the quadratic equation x^2 -8x + 15 = 0. You have two options of doing this, you can either substitute x=3 into the LHS and see that it evaluates to , or you could solve the quadratic equation and check that one of the roots is x=3.

    Use this logic here as well. Either plug z  =3+i into your quadratic and see if it evaluates to or solve it using the quadratic equation and see if one of your roots is indeed 3+i.
    THank you so much! I managed to solve it
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    (Original post by liemluji)
    THank you so much! I managed to solve it
    Good work! Glad I helped.
 
 
 
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