a) (5√432-2√75):√(2² x 5⁴)= = (5√2⁴x3³-10√3):50= = (60√3-10√3):50= = 50√3:50=√3 b) (√216-√726):√6-(√486-√294):√3= = (√2³x3³-√2x3x11²):√6-(√2x3⁵-√2x3x7²):√3= = (6√6-11√6):√6-(9√6-7√6):√3= = -5√6:√6-(2√6):√3= = -5-2√2  c) (√1805-√1445):√5-√5·(√845-√1620)= = (√5x19²-√5x17²):√5-√5·(√5x13²-√2²x3⁴x5)= = (19√5-17√5):√5-√5·(13√5-18√5)= = 2√5:√5-√5·(-5√5)= = 2+5=7 d) (√4375-√3087):√7-(√1008-√4732):√28= = (√5⁴x7-√3²x7³):√7-(√2⁴x3²x7-√2²x7x13²):2√7= = (25√7-21√7):√7-(12√7-26√7):2√7= = 4√7:√7-(-14√7):2√7= = 4+7=11