[tex]2a \sum (2x_i)^2 + 2b \sum x_i - 2 \sum x_i y_i [/tex] I need to set it equal to zero and solve for a.(adsbygoogle = window.adsbygoogle || []).push({});

[tex] 2a \sum x_i + 2nb - 2\sum y_i [/tex]

and solve for b.

I need a hint so i can start doing it, it confuses me all those adding symbols.

The Answer the book came up with is:

[tex] a= \frac{(n\sum x_i y_i - \sum x_i \sum y_i)} {(n \sum (x_i)^2 - (\sum x_i)^2} [/tex]

[tex] b= \frac{1 / n} (\sum y_i - a \sum x_i) [/tex]

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# Homework Help: Please help me out

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