$2^x=a$, $3^x=b$ va $5^x=c$ bo'lsa, $120^x$ sonini $a$, $b$ va $c$ orqali ifodalang.
- A. a^3b^2c
- B. a^2bc
- C. a^3bc
- D. a^3bc^2
Javob va yechimni ko‘rish
Javob: a^3bc
Berilgan $2^{x}=a$, $3^{x}=b$, $5^{x}=c$ tenglamalarini yodda tutib, $120$ning asosli ko‘paytmasini ajratamiz:
\[
120 = 2^{3}\cdot 3^{1}\cdot 5^{1}.
\]
Endi $120^{x}$ ni har bir asosning $x$‑darajaga ko‘tarilgan ko‘rinishida yozamiz:
\[
120^{x} = (2^{3}\cdot 3^{1}\cdot 5^{1})^{x}=2^{3x}\,3^{x}\,5^{x}.
\]
$2^{x}=a$, $3^{x}=b$, $5^{x}=c$ bo‘lgani uchun $2^{3x}=(2^{x})^{3}=a^{3}$. Shuning uchun
\[
120^{x}=a^{3}\,b\,c.
\]
Demak, $120^{x}$ ni $a$, $b$, $c$ orqali ifodalash natijasi \(\displaystyle a^{3}bc\), ya’ni **C** variantidir.