any equation having highest power of x is 2 then that equation is called quadratic equation. and power must be positive.let's take an example:-

(i) x2 + 6x - 4 = 0above equation has highest degree of the polynomial is 2 so it is a quadratic equation.

https://youtu.be/wSMHWy_IQyAmore details study

(2x+1)(3x+2)=6( x-1)(x-2); (6x^2+4x+3x+2)=6(x^2-2x-x+2); (6x^2+7x+2)=6(x^2-x+2); 6x^2+7x+2=6x^2-6x+12; 7x+6x=12-2; ; 13x=10; x=10/13; ; (xiii)16x^2-3=(2x+5)(5x-3); 16x^2-3=(10x^2-6x+25x-15); 16x^2-3=10x^2+19x-15); 16x^2-10x^2-3+15=19x; 6x^2+12-19x

x^2+1/x^2=3; . ( x+1/x)(x-1/x)=3; ; ( x^2+1/x)( x^2-1/ x^2)=3;

( x^2+1/x^2)=3; ( x+1/x)(x-1/x)= ( x^2+1/x)(x^2-1/x)=3,; ( x^2+1)( x^2-1)=3; x^4-x^2+x^2-1=3; x^4=3+1=4, x^4=(1)^4; x=1

viii)x+1/x=1; squares on both; (x+1/x)^2=1^2; x^2+(1/x^2)+2.x.1/x=1; x^2+1/x^2=1; iv)x-3/x=x^2; (x-3/x)^2=( x^2)^2; ) ( x^2+3/x^2-2.( x)(1/x)= x^4; x^2+3/x^2-2= x^4

(xiv)( x+2)^3=x^3-4; ( x+2)^3=x^3+8+3(x)2(x+2)= x^3+8+6x( x+2)=x^3-4; 8+6x^2+12x=-4; 6x^2+12x+4=0;

(xv)x(x+1)+8=( x+2)( x-2); x( x+1)+8=x^2+x+8; ( x+2)( x-2)=( x^2-2x+2x-4)=( x^2-4); x^2-4=x^2+x+8, x+8+4=x+12; x=-12

x= 3 is the correct answer

x= 3 is the correct answer

any equation have power 2 is called quadratic equation general quadratic equationax^2+bx+C=0x^2+2x+1=0x^2-6x-4=0