[tex]A \ quadratic \ equation \ is \ one \ which \ can \ be \ written \ in \ the \ form : \\\\ax^2+bx+c=0, \ \ \ a\neq 0 \\ \\Example : \ a)\\\\ x^2+x-6 =0 \\(x+3)(x-2)=0 \\ x+3=0\ \ \ or \ \ \ x-2 =0 \\x=-3 \ \ \ or \ \ x=2 \\\\\ b)\\\\x^2+7x=0 \\ \\ x(x+7)=0 \\x=0 \ \ \ or \ \ \ x+7=0\\x=0 \ \ \ or \ \ \ x=-7[/tex]
