(a) (tan69° + tan66°)/(1 - tan69°tan66°) = apply the formula tan(a+b) = = tan(69° + 66°) = tan(135°) = tan(180° + 45°) = 1. ANSWER (b) (sin45°cos15° + sin15°cos45°)/(sin45°cos15° - sin15°cos45°) = apply the formula sin(a+b) = sin(a)*cos(b) + cos(a)*sin(b) to the numerator; apply the formula sin(a-b) = sin(a)*cos(b) - cos(a)*sin(b) to the denominator. = = = = . ANSWER