Question
$3 m^2+2 m-7=0$
✓
Answer
$3 m^2+2 m-7=0 \text { compare with } ax ^2+ bx + c =0 $
$ \Rightarrow a =3, b=2 \text { and } c =-7 $
$ \therefore b ^2-4 ac =2^2-4(3)(-7) $
$ =4+84 $
$ =88 $
$ m=\frac{- b \pm \sqrt{ b ^2-4 ac }}{2 a } $
$ \Rightarrow m =\frac{-2 \pm \sqrt{88}}{2 \times 3} $
$ \Rightarrow m =\frac{-2 \pm \sqrt{88}}{6} $
$ \Rightarrow m =\frac{-2+2 \sqrt{22}}{6} \text { or } m =\frac{-2-2 \sqrt{22}}{6} $
$ \Rightarrow m =\frac{-1+\sqrt{22}}{3} \text { or } m =\frac{-1-\sqrt{22}}{3}$
$ \Rightarrow a =3, b=2 \text { and } c =-7 $
$ \therefore b ^2-4 ac =2^2-4(3)(-7) $
$ =4+84 $
$ =88 $
$ m=\frac{- b \pm \sqrt{ b ^2-4 ac }}{2 a } $
$ \Rightarrow m =\frac{-2 \pm \sqrt{88}}{2 \times 3} $
$ \Rightarrow m =\frac{-2 \pm \sqrt{88}}{6} $
$ \Rightarrow m =\frac{-2+2 \sqrt{22}}{6} \text { or } m =\frac{-2-2 \sqrt{22}}{6} $
$ \Rightarrow m =\frac{-1+\sqrt{22}}{3} \text { or } m =\frac{-1-\sqrt{22}}{3}$
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