(5⁶*125)/(25⁴) = (5⁶*5³)/((5²)⁴) = (5⁶⁺³)/(5⁸) = (5⁹)/(5⁸) = 5⁹⁻⁸ =5¹ = 5
А) x^2+4xy+5y^2+4y+2 = <span> (x^2 + 4xy + 4y^2) + (y^2 +4y + 4) - 2 =
</span>(x + 2y)^2 + (y + 2)^2 - 2
(x + 2y)^2 = min = 0 при x + 2y = 0 ⇔ x = -2y
(y + 2) ^2 = min = 0 при y = - 2
x = -2y = -2 * (-2) = 4
0 + 0 - 2 = -2
б) (x^2+4xy+4y^2)+2x+4y+2 = <span>(x + 2y)^2 + 2(x + 2y) + 1 + 1 =
(x + 2y + 1)^2 + 1
минимально при x + 2y + 1 = 0
x = -2y - 1
y </span>∈ R
0^2 + 1 = 1
в) x^2+y^2+z^2+2xy+2x+2y-4z+12 =
(x^2 + 2xy + y^2) + 2(x + y) + 1 + <span>(z^2 - 4z + 4) + </span><span>7 =
(x + y + 1)^2 + (z - 2)^2 + 7
аналогично
z = 2
x </span>∈ R
y = -1 - x
значение = 7
Решение дано в виде фотографии
log1/6(8-4/5*x)>-2 log6^(-1)(8-4/5*x)>-2 -log(8-4/5*x)>-2 log(8-4/5x)<2 2=log6(6^2)
8-4/5*x<36 -4/5*x<26 (*-5/4) x>-26*5/4 x>-65/2=-32.5 x>-32.5