Log₀ ₅ 0.5 log₉ 1/81 - 7^(log₇ 2)= 1 * log₉ 9⁻² - 2 = -2 - 2 = -4
(loga a = 1 a>0 a<>1)
log₃ 6 + log₃ 18 - log₃ 4 = log₃ (6*18 / 4) = log₃ 3³ = 3
9^(0.5 - log₃ 2) - log₃ (log₂ 8)) = (3^2)^0.5 / (3^2)^log₃ 2 - log₃(log₂ 2³)= 3 / 3^log₃ 4 - log₃ 3 = 3/4 -1 = -1/4 =-0.25
Х^2 - у^2 =72
<span>х + у = 9
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Метод подстановки:
х=9-у;
(9-y)^2-y^2=72
81-18y+y^2-y^2=72
81-18y=72
-18y=-9
y=0,5</span>