To simplify this expression, we first need to find the common denominator for the fractions:

287/357 * ((56/145) - (49/318))

Common denominator for 145 and 318 is 145 * 318 = 46010

Now, rewrite the expression with the common denominator:

287/357 ((56/145)(318/318) - (49/318)*(145/145))

287/357 * ((8968/46010) - (7105/46010))

287/357 * (1863/46010)

Now, multiply the fractions:

287 1863 / (357 46010)
534981 / 16432170

So, 287/357 * (56/145 - 49/318) simplifies to 534981/16432170.