7 1/4x-x=9 3/8

2 answers

mixed numbers are just a nuisance.
anyway, what is 7 1/4 - 1?
to find x, just divide 9 3/8 by that value.

Because
7 1/4 x - x = (7 1/4 - 1)x = 9 3/8
x = (9 3/8)/(7 1/4 - 1)
7 1/4 x - x = 9 3/8

x ( 7 1/4 - 1 ) = 9 3/8

7 1/4 = 7 + 1 / 4 = 28 / 4 + 1 / 4 = 29 / 4

7 1/4 - 1 = 7 1/4 - 4 / 4 = 29 / 4 - 4 / 4 = 25 / 4

9 3/8 = 9 + 3 / 8 = 72 / 8 + 3 / 8 = 75 / 8

x ( 7 1/4 - 1 ) = 9 3/8

x ∙ 25 / 4 = 75 / 8

25 x / 4 = 75 / 8

Cross multiply

25 x ∙ 8 = 75 ∙ 4

200 x = 300

Divide both sides by 200

x = 300 / 200 = 100 ∙ 3 / 100 ∙ 2 = 3 / 2 =

( 2 + 1 ) / 2 = 2 / 2 + 1 / 2 = 1 + 1 / 2 = 1 1/2