[tex]C = \frac{1}{4}n( \: a(1) \: + \: a(2) \: ) \\ [/tex]
Multiply sides by 4
[tex]4 \times C = 4 \times \frac{1}{4}n( \: a(1) + a(2) \: ) \\ [/tex]
[tex]4C = n( \: a(1) + a(2) \: )[/tex]
Divided sides by n
[tex] \frac{4C}{n} = \frac{n}{n}( \: a(1) + a(2) \: ) \\ [/tex]
[tex] \frac{4C}{n} = a(1) + a(2) \\ [/tex]
Subtract sides - a (2)
[tex] \frac{4C}{n} - a(2) = a(1) + a(2) - a(2) \\ [/tex]
[tex] \frac{4C}{n} - a(2) = a(1) \\ [/tex]
[tex]a(1) = \frac{4C}{n} - a(2) \\ [/tex]
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Done ♥️♥️♥️♥️♥️
