Question

Which of the following is not a quadratic equation * 1 point x² + 3x – 5 = 0 x + 2x +2 = 0 3 + x + x² = 0 x² – 9 = 0

Answer 1

$\huge\mathbb{QUESTION :}$

• Which of the following is not a quadratic equation ?

a) $\rm {x}^{2} + 3x - 5 = 0$

b) $\rm{x + 2x + 2 = 0}$

c) $\rm{}3 + x + {x}^{2}$

d) $\rm {x}^{2} - 9 = 0$

$\huge \mathbb{ANSWER : } \\ \\ \implies \: \: \text{ Option (\red{b}) is correct answer.}$

• To check whether a given Equation is Quadratic or not, we need to know the highest power of the equation, which should be 2.

Thus,

• Simplifying each of given equations, so that its highest power can be known.

$\rm{}a) \: \: {x}^{2} + 3x - 5 = 0 \\ \small = > \text{Its highest power(degree) is 2.} \\ \therefore \textsf{ \: \: \underline{ \: It is Quadratic Equation. } \: }$

$\rm{}b) \: \: \: x + 2x + 2 \\ \rm{}\implies 3x + 2 \\ \\ \small = > \text{Its highest power(degree) is 1.} \\ \small\therefore \textsf{ \: \: \underline{ \: It is not Quadratic Equation. } \: }$

$\rm{}c) \: \: \: 3 + x + {x}^{2} \\ \rm{}\implies {x}^{2} + x + 3 \\ \\ \small = > \text{Its highest power(degree) is 2.} \\ \therefore \textsf{ \: \: \underline{ \: It is Quadratic Equation. } \: }$

$\rm{}d) \: \: \: \: {x}^{2} - 9 \\ \small = > \text{Its highest power(degree) is 2.} \\ \therefore \textsf{ \: \: \underline{ \: It is Quadratic Equation. } \: }$

Hence,

• It is concluded that ([tex] \rm{x + 2x + 2 = 0} = 3x +2 [tex]) is not quadratic equation.