5^-12/5^-11=5^1=5.
по форму a^n/a^m=a^n-m
|x|-8=-5
|x|=8-5
|x|=3
x=3 или х= -3
3X + Y = 2
X - 2Y = 7
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X = 2Y + 7
3 * ( 2Y + 7) + Y = 2
6Y + 21 + Y = 2
7Y = - 19
Y = - 19/7 = - 2 ( 5/7 )
X = 2 * ( - 19/7 ) + 7 = - 38/7 + 7 = - 5 ( 3/7 ) + 7 = 1 ( 4/7 )
a² - 7a + 3 = 2 ⇒ a² - 7a = 2 - 3 = - 1
2a² - 14a = 2(a² - 7a) = 2 * (- 1) = - 2
2a² - 14a + 10 = - 2 + 10 = 8
Ответ : 8
14*0,81*0,36=4.0824.......................