diketahui |a+b| = 10 dan |a-b| = 6 . maka a.b ?

|a + b| = 10 => |a + b|^2 = 10^2 => a^2 + 2a.b + b^2 = 100
|a - b| = 6 ==> |a - b|^2 = 6^2 ==> a^2 - 2a.b + b^2 = 36
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................................................................ 0 + 4a.b + 0 = 64 => a.b = 64/4 = 16