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Question
Solve the following quadratic equation by factorisation.
7m2 = 21m
Solution
\[7 m^2 = 21m\]
\[\Rightarrow 7 m^2 - 21m = 0\]
\[ \Rightarrow 7m\left( m - 3 \right) = 0\]
\[ \Rightarrow 7m = 0 \text{ or } m - 3 = 0\]
\[ \Rightarrow m = 0 \text{ or } m = 3\]
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