1) -1 - 1 = -2
2) 71 - 64 = 7
3) √2*(1 - 2 + 5) = 4√2
4) a) log7 (49) = 2; b) log2 (1/4) = -2; c) log(1/3) (27) = -3;
d) lg 100 - 2log4 (16) = 2 - 2*2 = 2 - 4 = -2
5) a) x = log2 (9); b) x = 2^6 = 64; c) x^3 = 8; x = 2
6) log7 (1/5) + log7 (15) = log7 (1/5*15) = log7 (3)
log7 (54) - log7 (18) = log7 (54/18) = log7 (3)
Да, равенство верно
7) (1/3 + 1/2) : (1/6 + 1/2) = (2/6 + 3/6) : (1/6 + 3/6) = (5/6) : (4/6) = 5/4
Интересно, почему вам рядом с логарифмами (7 класс советской школы) дали сумму дробей (4 класс советской школы)?
8) AB = CD = BD*cos 60 = 2a*1/2 = a
BC = AD = BD*sin 60 = 2a*√3/2 = a√3
P = 2a + 2a√3 = 2a*(1 + √3)
S = a*a√3 = a^2*√3