Question

If 1/x + 1/3x equals 4 then what is x

Answer 1

Answer:

$\huge\boxed{x=\dfrac{1}{3}}$

Step-by-step explanation:

$\dfrac{1}{x}+\dfrac{1}{3x}=4\\\\\text{Domain:}\ x\neq0\\\\\text{find LCD}=3x\\\\\dfrac{1\cdot3}{x\cdot3}+\dfrac{1}{3x}=4\\\\\dfrac{3}{3x}+\dfrac{1}{3x}=4\\\\\dfrac{3+1}{3x}=4\\\\\dfrac{4}{3x}=\dfrac{4}{1}\qquad\text{cross multiply}\\\\(3x)(4)=(4)(1)\\\\12x=4\qquad\text{divide both sides by 12}\\\\\dfrac{12x}{12}=\dfrac{4}{12}\\\\x=\dfrac{4:4}{12:4}\\\\x=\dfrac{1}{3}\in D$