How To Derive The Quadratic Formula 8 Steps
ax2+bx+c=0{\displaystyle ax^{2}+bx+c=0} The only condition is that a≠0,{\displaystyle a\neq 0,} because otherwise, the equation reduces to a linear equation. See if you can find general solutions for the special cases where b=0{\displaystyle b=0} and where c=0. {\displaystyle c=0. } ax2+bx=−c{\displaystyle ax^{2}+bx=-c} x2+bax=−ca{\displaystyle x^{2}+{\frac {b}{a}}x={\frac {-c}{a}}} x2+2b2ax+b24a2=b24a2−ca(x+b2a)2=b24a2−ca{\displaystyle {\begin{aligned}x^{2}+2{\frac {b}{2a}}x+{\frac {b^{2}}{4a^{2}}}&={\frac {b^{2}}{4a^{2}}}-{\frac {c}{a}}\\left(x+{\frac {b}{2a}}\right)^{2}&={\frac {b^{2}}{4a^{2}}}-{\frac {c}{a}}\end{aligned}}} Here, it is clear why a≠0,{\displaystyle a\neq 0,} since a{\displaystyle a} is in the denominator, and you cannot divide by 0....