3^x-1-3^x-2=18 и 9^x-1-3^x-2=30 решить - вопрос №3482070313218913230 от inakuleshova19 08.02.2021 18:23

Question

Алгебра: 3^x-1-3^x-2=18 и 9^x-1-3^x-2=30 решить

inakuleshova19 · Answer

1)  3^(x - 1) - 3^(x - 2) = 18(1/3)*(3^x) - (1/9)*(3^x) = 18(2/9)*(3^x) = 18 3^x = 813^x = 3^4x = 42) 9^(x - 1) - 3^(x - 2) = 30(1/9)*3^(2x) - (1/9)*(3^x)  - 30 = 03^(2x) - (3^x) - 270 = 0D = 1 + 4*1*270 = 10813^x = (1 - √1081)/2 03^x = (1 + √1081)/2x = log₃ (1 + √1081)/2...