Math, asked by manvig1294, 9 months ago

for what calue of k will the equation (k+4)x²+(k+1)x+1=0 have real and equal roots​

Answers

Answered by Nikhil0204
0

\large\red{ANSWER} \\

(k + 4) {x}^{2}  + (k + 1)x + 1 = 0 \\

</p><p>D =  {b}^{2}  - 4ac \\  ={ (k + 1) }^{2} - 4 \times (k + 4) \times 1 \\  =  {k}^{2}   + 1 + 2k - 4k + 16 \\  =  {k}^{2}   - 2k + 17 \\

ACCORDING \: \:   TO  \:  \: QUESTION,   \\ equation \:  has  \: real  \: and  \: equal \:  roots \\ </p><p>=&gt;D=0 \\

 =  &gt;  {k }^{2}  - 2k + 17 = 0 \\

D =  {b}^{2}  - 4ac \\  =  {( - 2)}^{2}  - 4 \times 1 \times 17 \\  = 4 - 68 \\  =  - 64 &lt; 0 \\  =  &gt; no \: real \: roots \: exist \: or \: imaginary \: roots \\

x =  \frac{ - b +  -  \sqrt{D} }{2a}  \\ x =  \frac{ - ( - 2) +  -  \sqrt{ - 64} }{2 \times 1}  \\  =  \frac{2 +  -  \sqrt{ {8}^{2} {i}^{2}  } }{2}  \\  =  \frac{2 +  - 8i}{2}  \\  = 1 +  - 4i \\

 =  &gt; x = 1 + 4i \: or \: x = 1 - 4i

Here this is the value of k.

=> k=1+4i

or k=1-4i

where i(iorta)=√-1

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Answered by venkatavineela3
0

Answer:

Step-by-step explanation:

b=k+1

a=k+4

c=1

b^2-4ac=0 to be real and equal

(k+1)^2-4(k+4)=0

k^2+1+2k-4k-4=0

k^2-2k-3=0

k^2-3k+k-3=0

k(k-3)+1(k-3)=0

k=3,-1

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