text: only for brainiacs? if the roots of the quadratic equation x^2 + pq + q = 0 r tan 15 deg & tan 30 then find value for 2 + q - p.i m only 13. that one is easy if you can write the question correctly. please write the question in a proper manner and don't use capital letters in that way. it only makes people's head dizzy if you use caps at every single letter of the question.  x^2 + pq + q = 0 (x - tan(15) )(x - tan(30) ) = 0 x^2 - x * tan(30) - x * tan(15) + tan(15) * tan(30) = 0 x^2 - x * (tan(30) - tan(15)) + tan(15) * tan(30) = 0  thus: pq = - x * (tan(30) - tan(15)) q = tan(15) * tan(30)  substitution. insert q = ... into pq = ...  p (tan(15) * tan(30)) = - x * (tan(30) - tan(15)) p = [- x * (tan(30) - tan(15)) ] / [tan(15) * tan(30)]  now we know the value of p and q (although in variables), insert that into 2 + q - p  2 + tan(15)*tan(30) - [-x*(tan(30)-tan(15))]/[tan(15)*tan(30)]  whew, confusing equation, let's just make tan(15)*tan(30) be a. and tan(30)-tan(15) be b.  2 + a - [-x * b]/[a]  now this becomes a function. the solution is the function f(x) = 2 + a - [-x * b]/[a] where a = tan(15)*tan(30) = approx. -5.5493377957377570208698828633358 and b = tan(30)-tan(15) = approx. 5.4829212349626777884063492759597  or you can use several significant figure say three:  f(x) = 2 - 5.55 - [-x * 5.48]/[-5.55] f(x) = -3.55 - [x * 5.48]/[5.55]