Вправи 301 - 400 » 340 (3-6)

3) (5 • 8 • 12)–1 = x • 8–1 • 12–1; 5–1 • 8–1 • 12–1 = x • 8–1 • 12–1; 5–1 • 96–1 = x • 96–1 |: 96–1; x = 5–1 = 1/5. 4) (2/5)–4 = 2^(-4)/x^(-4) ; 2^(-4)/5^(-4) = 2^(-4)/x^(-4) ; x = 5. 5) (1/7)–9 = 1/x^(-9) ; 1^(-9)/7^(-9) = 1/x^(-9) ; –1/7^(-9) = 1/x^(-9) ; x = –7. 6) (11/3)–7 = x^(-7)/3^(-7) (4/3) = x^(-7)/3^(-7) ; 4^(-7)/3^(-7) = x^(-7)/3^(-7) ; x = 4.