For what value of $k$ the quadratic equation has equals roots, the equation is \[\left( {k - 2} \right){x^2} + 2\left( {2k - 3} \right)x + (5k - 6) = 0\]\[\left( {k - 2} \right){x^2} + 2\left( {2k - 3} \right)x + (5k - 6) = 0\] ?
Answer
547.8k+ views
Hint: The quadratic equation has been given to have equal roots. As a result, the determinants will be zero. We know that where a, b, and c are the coefficients of \[{x^2}\] , x, and constant terms of the provided quadratic equation in the question, respectively. To get the required value of k, solve the quadratic equation of k.
Complete step by step answer:
We know that if a polynomial equation's highest degree (highest power of the variable) is 2, the polynomial equation is quadratic. We also know that the universal quadratic equation looks like this:
\[ \Rightarrow a{x^2} + bx + c = 0\].........(1)
We know that the discriminant is defined as $D = b^2- 4ac$, where $a, b$ and $c$ are the coefficients of \[{x^2}\] , $x$ and constant terms respectively. Since, we have given that the equation has equal roots. So, the discriminant will be equal to zero.We will equate discriminant equals to zero. When We will compare equation \[\left( {k - 2} \right){x^2} + 2\left( {2k - 3} \right)x + (5k - 6) = 0\] with equation 1.
We get \[a = k - 2\], \[b = 4k - 6\], \[c = 5k - 6\]. We will put D equals to zero and the other values. We will put the value of a, b and c.
\[ \Rightarrow 0 = \;{\left( {{\mathbf{4k}} - {\mathbf{6}}} \right)^2} - {\mathbf{4}} \times \left( {{\mathbf{k}} - {\mathbf{2}}} \right)\left( {{\mathbf{5k}} - {\mathbf{6}}} \right)\]
We will expand the square term and multiply the second term
\[ \Rightarrow 0 = 16{k^2} + 36 - 48k - 20{k^2} + 64k - 48\]
\[ \Rightarrow 0 = 4{k^2} - 16k + 12\]
We will divide whole equation by 4
\[ \Rightarrow 0 = {k^2} - 4k + 3\]
We will use mid-term split formula
\[ \Rightarrow 0 = {k^2} - 3k - k + 3\]
\[ \Rightarrow 0 = \left( {k - 3} \right)\left( {k - 1} \right){\text{ }}\]
\[ \therefore k = 3\] and \[k = - 1\]
Hence, for k=3 and \[k = - 1\] the equation \[\left( {k - 2} \right){x^2} + 2\left( {2k - 3} \right)x + (5k - 6) = 0\] has equal roots.
Note: When we encounter this type of problem, we must first form the generic quadratic equation, which we will compare to the supplied equation to get the values of a, b, and c. Then, using the condition given in question, we find the equation in terms of k.
Complete step by step answer:
We know that if a polynomial equation's highest degree (highest power of the variable) is 2, the polynomial equation is quadratic. We also know that the universal quadratic equation looks like this:
\[ \Rightarrow a{x^2} + bx + c = 0\].........(1)
We know that the discriminant is defined as $D = b^2- 4ac$, where $a, b$ and $c$ are the coefficients of \[{x^2}\] , $x$ and constant terms respectively. Since, we have given that the equation has equal roots. So, the discriminant will be equal to zero.We will equate discriminant equals to zero. When We will compare equation \[\left( {k - 2} \right){x^2} + 2\left( {2k - 3} \right)x + (5k - 6) = 0\] with equation 1.
We get \[a = k - 2\], \[b = 4k - 6\], \[c = 5k - 6\]. We will put D equals to zero and the other values. We will put the value of a, b and c.
\[ \Rightarrow 0 = \;{\left( {{\mathbf{4k}} - {\mathbf{6}}} \right)^2} - {\mathbf{4}} \times \left( {{\mathbf{k}} - {\mathbf{2}}} \right)\left( {{\mathbf{5k}} - {\mathbf{6}}} \right)\]
We will expand the square term and multiply the second term
\[ \Rightarrow 0 = 16{k^2} + 36 - 48k - 20{k^2} + 64k - 48\]
\[ \Rightarrow 0 = 4{k^2} - 16k + 12\]
We will divide whole equation by 4
\[ \Rightarrow 0 = {k^2} - 4k + 3\]
We will use mid-term split formula
\[ \Rightarrow 0 = {k^2} - 3k - k + 3\]
\[ \Rightarrow 0 = \left( {k - 3} \right)\left( {k - 1} \right){\text{ }}\]
\[ \therefore k = 3\] and \[k = - 1\]
Hence, for k=3 and \[k = - 1\] the equation \[\left( {k - 2} \right){x^2} + 2\left( {2k - 3} \right)x + (5k - 6) = 0\] has equal roots.
Note: When we encounter this type of problem, we must first form the generic quadratic equation, which we will compare to the supplied equation to get the values of a, b, and c. Then, using the condition given in question, we find the equation in terms of k.
Recently Updated Pages
A Paragraph on Pollution in about 100-150 Words

What is BLO What is the full form of BLO class 8 social science CBSE

10 examples of friction in our daily life

Draw a diagram of nephron and explain its structur class 11 biology CBSE

Write structures of the following compounds i 2 Chloro3methylpentane class 11 chemistry CBSE

XIX+XXX A 49 B 51 C 55 D 44 class 5 maths CBSE

Trending doubts
Explain the Treaty of Vienna of 1815 class 10 social science CBSE

1 GB equals how many MB?

10 examples of evaporation in daily life with explanations

What is the full form of POSCO class 10 social science CBSE

Which is the hottest planet in the Solar system A Earth class 10 social science CBSE

Name any four life processes in living things class 10 biology CBSE

