Question

Solve for x :5x/4 -6/7 =3/8

Answer 1

Given :

$\dfrac{5x}{4} - \dfrac{6}{7} = \dfrac{3}{8}$

To find :

Value of x

Solution :

⟹$\dfrac{5x}{4} - \dfrac{6}{7} = \dfrac{3}{8}$

⟹$\dfrac{5x}{4} = \dfrac{3}{8} +\dfrac{6}{7}$

LCM of 8 and 7 = 56

⟹$\dfrac{5x}{4} = \dfrac{21 + 48}{56}$

⟹$\dfrac{5x}{4} = \dfrac{69}{56}$

⟹${5x} = \dfrac{69 \times 4}{56}$

4×14 = 56

⟹${5x} = \dfrac{69 }{14}$

⟹${x} = \dfrac{69 }{14} \times \dfrac{1}{5}$

⟹${x} = \dfrac{69 }{70}$

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Verification of answer :-

Now to verify the answer. put x = 69/70 in 5x/4 -6/7 =3/8.

⟹$LHS \: = \dfrac{5x}{4} - \dfrac{6}{7}$

⟹$(\dfrac{5 }{4} \times\dfrac{69 }{70} )- \dfrac{6}{7}$

5 × 14=70

⟹$(\dfrac{1}{4} \times\dfrac{69 }{14} )- \dfrac{6}{7}$

14×4 = 56

⟹$\dfrac{69 }{56} - \dfrac{6}{7}$

LCM of 56 and 7 = 56

⟹$\dfrac{(69 - 48) }{56}$

⟹$\dfrac{21 }{56}$

⟹$\dfrac{3 }{8}$

Therefore, LHS = RHS. Hence verified

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Answer 2

Given :-

$\to\sf \frac{5x}{4} - \frac{6}{7} = \frac{3}{8}$

To Find :-

$\to\sf Value \: of \: \boxed{\bf x}$

Solution :-

$\sf \frac{5x}{4} - \frac{6}{7} = \frac{3}{8}$

$:\implies\sf \frac{5x}{4} = \frac{3}{8} + \frac{6}{7}$

$:\implies\sf \frac{5x}{4} = \frac{21 + 48}{56}$

$:\implies\sf \frac{5x}{4} = \frac{69}{56}$

$:\implies\sf280x = 276$

$:\implies\sf x = \frac{\cancel{276}}{\cancel{280}}$

$:\implies\underline{\boxed{\blue{\bf x = \frac{69}{70}}}}$