Answer:
A quadratic equation is an equation of the form ax^2 + bx + c = 0, where a, b, and c are constants, and x is a variable.
The equations that are quadratic equations are:
(i) x^ 2 + 6 x − 4 = 0
(v) 2 x^ 2 − √ 3 x + 9 = 0
The equations that are not quadratic equations are:
(ii) √ 3 x^ 2 − 2 x + 1/ 2 = 0
(iii) x^ 2 + 1/ x^ 2 = 5
(iv) x − 3/ x = x ^ 2
(vi) x ^ 2 − 2 x − √ x − 5 = 0
(vii) 3 x ^ 2 − 5 x + 9 = x 2 − 7 x + 3
(viii) x + 1 x = 1
In (ii) √ 3 x^ 2 − 2 x + 1/ 2 = 0 the coefficient of x^2 is not a real number.
In (iii) x^ 2 + 1/ x^ 2 = 5 the equation is not in the form of ax^2 + bx + c = 0
In (iv) x − 3/ x = x ^ 2 the equation is not in the form of ax^2 + bx + c = 0
In (vi) x ^ 2 − 2 x − √ x − 5 = 0 the equation is not in the form of ax^2 + bx + c = 0
In (vii) 3 x ^ 2 − 5 x + 9 = x 2 − 7 x + 3 both sides are not equal
In (viii) x + 1 x = 1 the equation is not in the form of ax^2 + bx + c = 0
So, the equations that are quadratic equations are (i) and (v).
Explanation: