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# discriminant C1 question Watch

1. 2x(2)+kx-(k+2)=0....this equation has 2 equal roots.Find the value of k.

im getting the answer as -4, but the answers say it should be 4.
can someone help me out
thanks
2. (Original post by pakizrulez)
2x(2)+kx-(k+2)=0....this equation has 2 equal roots.Find the value of k.

im getting the answer as -4, but the answers say it should be 4.
can someone help me out
thanks
3. (Original post by pakizrulez)
2x(2)+kx-(k+2)=0....this equation has 2 equal roots.Find the value of k.

im getting the answer as -4, but the answers say it should be 4.
can someone help me out
thanks
c in your discriminant should be -k-2 because the eqn is not of the form:
4. (Original post by pakizrulez)
2x(2)+kx-(k+2)=0....this equation has 2 equal roots.Find the value of k.

im getting the answer as -4, but the answers say it should be 4.
can someone help me out
thanks
a=2, b = k, c = -(k+2)
k^2 - 4(2)[-(k+2)] = 0
k^2 + 8(k+2) = 0
k^2 + 8k + 16 = 0
(k+4)^2 = 0
k = -4

I agree with you.

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