Question

Solve x - 3 1/8 = 5/12

Answer 1

Answer:

$\large\boxed{x=\dfrac{85}{24}=3\dfrac{13}{24}}$

Step-by-step explanation:

Convert the mixed number to the fraction:

$3\dfrac{1}{8}=\dfrac{3\cdot8+1}{8}=\dfrac{25}{8}$

METHOD 1:

$x-3\dfrac{1}{8}=\dfrac{5}{12}\\\\x-\dfrac{25}{8}=\dfrac{5}{12}\\\\\text{the common denominator is 24}\\\\x-\dfrac{25}{8}=\dfrac{5}{12}\qquad\text{multiply both sides by 24}\\\\24x-(3)(25)=(2)(5)\\\\24x-75=10\qquad\text{add 75 to both sides}\\\\24x=85\qquad\text{divide both sides by 24}\\\\\boxed{x=\dfrac{85}{24}}$

METHOD 2:

$x-3\dfrac{1}{8}=\dfrac{5}{12}\qquad\text{add}\ 3\dfrac{1}{8}\ \text{to oboth sides}\\\\x=\dfrac{5}{12}+3\dfrac{1}{8}\\\\x=\dfrac{5\cdot2}{12\cdot2}+3\dfrac{1\cdot3}{8\cdot3}\\\\x=\dfrac{10}{24}+3\dfrac{3}{24}\\\\x=3\dfrac{10+3}{24}\\\\\boxed{x=3\dfrac{13}{24}}$