Find the value of k so that the equation has equal roots x²-2(5+2k)x +3(7+10k)=0
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Equal roots means D=0
i. e. b square - 4ac=0
(-10-4k) square - 4(1)(21+30k)=0
100+16k square +80k-84-120k=0
16k square - 40k +16=0
16k square - 32k-8k+16=0
16k (k-2)-8(k-2)=0
(16k-8)(k-2)=0
k=1/2 or 2
i. e. b square - 4ac=0
(-10-4k) square - 4(1)(21+30k)=0
100+16k square +80k-84-120k=0
16k square - 40k +16=0
16k square - 32k-8k+16=0
16k (k-2)-8(k-2)=0
(16k-8)(k-2)=0
k=1/2 or 2
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