(1) 1/4√256+√0.25
=1/4×16+0.5
=4+0.5
=4.5
(2) 2√2+3√5-3√2-3√5
=(2√2-3√2)+(3√5-3√5)
=-√2
(3) √(﹣2/5)²-√1-(﹣4/5)²
=2/5-√9/25
=2/5-3/5
=-1/5
(1) 1/4√256+√0.25
=1/4×16+0.5
=4+0.5
=4.5
(2) 2√2+3√5-3√2-3√5
=(2√2-3√2)+(3√5-3√5)
=-√2
(3) √(﹣2/5)²-√1-(﹣4/5)²
=2/5-√9/25
=2/5-3/5
=-1/5