equivalent fractions can be found by multiplying numerator and denominator by the same number.
for example : 2/5 * 3/3 = 6/15......2/5 and 6/15 are equivalent. Just like 2/5 * 4/4 = 8/20......2/5 and 8/20 are equivalent...so basically, if u multiply the numerator by a certain number, and the denominator by that same number, u will get an equivalent fraction.
Now to ur problem...
x 54
------ = -----
7 42
now look at ur denominators....7 x what = 42 ? 7 x 6 = 42...so u have multiplied the denominator by 6....so u would have to multiply the numerator by 6.....or divide by 6....54/6 = 9.....or 9 x 6 = 54. So that missing value is 9.
9/7 = 54/42
check..
9/7 * 6/6 = 54/42 (equivalent)
