=2√2−√3√2+√3×√2−√3√2−√3 =2√2(√2)+(2√2)(−√3)−√3(√2)−√3(−√3)(√2)2−(√3)2 =2×2−2√6−√6+32−3 =4−3√6+3−1 =7−3√6−1 =7−1−3√6−1 =−7+3√6 =3√6−7