(2-√3)^2 *(7+4√3)+3√12*1/4

(2-√3)^2 *(7+4√3)+3√12*1/4  = (2-√3)² *(√3²+4√3+ 2²)+3√(3*4)*1/4 = (  2-√3)²(2+√3)² + 6√3/4 = ((2-3)(2+√3))² + 3√3/2 = 4-3 + 3√3/2 = (2+3√3)/2