║ 10х - 9у = 8, - умнож. все на 3,
║ 21у + 15х = 0,5, - умнож. все на -2,
║ 30х - 27у = 24,
║ -42у - 30х = -1,
складываем левые и правые части:
30х - 27у - 42у - 30х = 24 - 1,
-69у = 23,
у = -1/3,
из 1 ур-ия:
х = (8 + 9у) / 10 = (8 - 9*1/3) / 10 = (8 - 3) / 10 = 5/10 = 1/2 (или 0,5),
ответ: (1/2; -1/3)
Ответ:всего лежыт 3 точки (x3 , x5 , x8)
Пошаговое объяснение:
1) 2^(1/2)=√2
5^(1/3)=∛5
3^(3/4)=⁴√(3)³
2) а) [ m-n^(1/2)]²+ [ m+n^(1/2)]²=m²-2m·n^(1/2)+n+m²+2m·n^(1/2)+n=
=2m²+2n
б) [ m^(1/3)+2n^(1/2)]² - [ m^(1/3)-2n^(1/2)]²=
={[ m^(1/3)+2n^(1/2)] -[ m^(1/3)-2n^(1/2)]}·
·{[ m^(1/3)+2n^(1/2)]+[ m^(1/3)-2n^(1/2)]}=
=4n^(1/2)·2m^(1/3)=8n^(1/2)·m^(1/3)
в)[ m^(1/4)-n^(1/2)]· [ m^(1/4)+n^(1/2)]=m^(1/2)-n
г) [ m^(1/2)+n]· [ m-m^(1/2)n+n²)]=m^(3/2)+n³
3) [7^(1/2)-3^(1/2)]²+[7^(1/2)+3^(1/2)]²=
=7-2[7^(1/2)·3^(1/2)]+3 +7+2[7^(1/2)·3^(1/2)]+3=14+6=20
4)(x-y)/[x^(1/2)-y^(1/2)]=[x^(1/2)+y^(1/2)]
5•35=175
5•40=200
175+200=375
375-140-120=115
Ответ 115 кг
80:8=10 (раз)
Ответ: в 10 раз