1) 10(n+m)-4(2m+7n)=10n+10m-8-14n=10n-14n+10m-8=10m-4n+8
2)11(5c+d)+3(d+c)=55c+11d+3d+3c=58c+14d
(0,3a⁵+0,5b²)³= (0,3а⁵)³+3*(0,3а⁵)² *0,5b²+3*0,3a⁵ *(0,5b²)²+(0,5b²)³=
= (3/10 a⁵)³+3*(3/10 a⁵)² * 1/2 b²+3 * 3/10 a⁵ *(1/2 b²)²+(1/2 b²)³=
= 27/1000 a¹⁵+3 * 9/100 a¹⁰ * 1/2 b²+3 * 3/10 a⁵ * 1/4 b⁴+ 1/8 b⁶=
=27/1000 a¹⁵+27/200 a¹⁰ b²+3 * 9/10 a⁵b⁴+ 1/8 b⁶
3 15 9
-- х --- = --
20 1 4
7 15 7
-- х -- = --
30 1 2
9 14 23
--- + --- = ---
4 4 4
23
--
ответ 4