4,2tu+2,1tv-4,9tp=7t×(0,6u+0,3v-0,7p)
4у-3у=5+1
у=6
Проверка:4*6-1=3*6+5
24-1=18+5
23=23
1-D
2-B
1) 27*5 X^6 y^10
2) 16 a^4 b^20 * 25 a^14 b^4
√(x^2 - 1 ) = 1 - x
ОДЗ
x ≤ 1
x^2 - 1 = (x - 1)^2
(x - 1)(x + 1) - (x - 1)^2 = 0
(x - 1)(x + 1 - (x - 1)) = 0
(x - 1)(x + 1 - x + 1) = 0
(x - 1) *2 = 0
x - 1 = 0
x = 1
Ответ
1