Question: The formulas for the least square line were found by solving the system of equations

\[\begin{aligned} & nb+m\left( \sum{x} \right)=\sum{y} \\ & b\left( \sum{x} \right)+m\left( {{\sum{x}}^{2}} \right)=\sum{xy} \\ \end{aligned}\]

Solve these equations for b and m to show that

\[\begin{aligned} & m=\frac{n\left( \sum{xy} \right)-\left( \sum{x} \right)\left( \sum{y} \right)}{n\left( \sum{{{x}^{2}}} \right)-{{\left( \sum{x} \right)}^{2}}} \\ & b=\frac{\sum{y-m\left( \sum{x} \right)}}{n} \\ \end{aligned}\]