1) Вычислить: 1) 0,4√6400; 2) 100√0,16 − (1/26)√169; 3) (2/9)·√(5 1/16); 4) √784 − 10√2,56; 5) 2,5·√3,24 − (1/2)·√225; 6) 4 − (1/4)·√(5 11/49).

1. \(0.4\sqrt{6400}=0.4\cdot80=32\).
2. \(100\sqrt{0.16}-\frac{1}{26}\sqrt{169}=100\cdot0.4-\frac{13}{26}=40-0.5=39.5\).
3. \(\frac{2}{9}\sqrt{5\frac{1}{16}}=\frac{2}{9}\sqrt{\frac{81}{16}}=\frac{2}{9}\cdot\frac{9}{4}=\frac{1}{2}\).
4. \(\sqrt{784}-10\sqrt{2.56}=28-10\cdot1.6=12\).
5. \(2.5\sqrt{3.24}-\frac{1}{2}\sqrt{225}=2.5\cdot1.8-\frac{1}{2}\cdot15=4.5-7.5=-3\).
6. \(4-\frac{1}{4}\sqrt{5\frac{11}{49}}=4-\frac{1}{4}\sqrt{\frac{256}{49}}=4-\frac{1}{4}\cdot\frac{16}{7}=4-\frac{4}{7}=\frac{24}{7}\).

Ответ: 1) 32; 2) 39,5; 3) \(\frac{1}{2}\); 4) 12; 5) −3; 6) \(\frac{24}{7}\).