Question

(1/4-0,7*2/4)*4
(1/7-0,9*2/9)*7
-2ав+3(4а+в)²= при а√7,в=√3
помогите,пожалуйста.​

Answer 1

1)

$( frac{1}{4} - frac{7}{10} times frac{1}{2} ) times 4 = ( frac{1}{4} - frac{7}{20} ) times 4 = - frac{1}{10} times 4$

2)

$( frac{1}{7} - frac{9}{10} times frac{2}{9} ) times 7 = ( frac{1}{7} - frac{1}{5} ) times 7 = - frac{2}{35} times 7 = - frac{2}{5}$

3)

$= - 2 sqrt{21} + 345 + 24 sqrt{21} = 22 sqrt{21} + 345$