(10√6):(4√8-√18)+(-4√21):(4√28-2√63) = 10√6(8√2 + 3√2) / (16 x 8 - 18) - 4√21 (4√28 + 2√63) / (16 x 28 - 4 x 63) = 10√6 x 11√2 / 110 - 4√21 (8√7 + 6√7) / (448 - 252) = 2√3 - 4√21 x 14√7 / 196 = 2√3 - 7 x 4 x 14 x √3 /196 =
= 2√3 - 392 √3 / 196 = 2√3 - 2√3 = 0
