If a, b, c, d are the missing numbers:
(a-b/c)×d=10,
which can be interpreted:
((a-b)/c)×d=10 or (a-(b/c))×d=10.
So: (a-b)d=10c or (ac-b)d=10c.
Since {a,b,c,d}={8,7,4,3}, 10c/d must be a whole number.
(1) a-b=10c/d or (2) ac-b=10c/d.
Consider single-digit numbers first.
(1) If c=8, then d=4 and the RHS=20; if c=4, then d=8 and the RHS=5. (1) doesn't work, because a-b=7-3=4.
(2) If c=8, then d=4, but ac-b can only be 8a-b=8×3-7=17; or 8a-b=8×7-3=53, neither of which work.
If c=4, then d=8, ac-b becomes 4a-b=4×3-7=5, which works:
(3-(7/4)×8=10, (12-7)/4×8=(5/4)×8=10.