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)

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