Unsimplified Fraction

Geometry Level 2

If we have $\dfrac { \sin(A+B) }{ \cos(A-B) } =\frac { 1+5 }{ 1-5 }$ then find the value of $\tan\left(\dfrac { \pi }{ 4 } -A\right)\tan\left(\dfrac { \pi }{ 4 } -B\right).$

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