529) Aflați numărul a, dacă:
a) 310-ax (100-30 x 3) = 280;
b) 64-120: (30 x 2:10)-a = 40;
c) 406-4 x [ax (30-20:5:4)] = 58;
d) [21-(648:24+ a): 7] x3+55=100;
e) [1860:3+(a+164): 2+7]:8 = 100
f) 110-[a-15 x (252-15 x 16)] = 18
g) [18+ (a-2016): 3] × 3-15 = 2 019
h) 5+ [32 (10: ax 4+12)] x7 = 89
i) 8-[6400:16-(360-ax 2) x 5]: 20 = 3
j) [(36-46:2x0) + (a x 7-3 x 12)] : 7=6
k) 5+(90+(20-135: ax 3)-54] x 6 = 251
l) [6 x (12: a+7x8):3-2x9] x 7+ 2 x 39 = 792 m) 7-[100 x 68: 17-5 x (60 x 6-2 x a)]: 20 = 2
n) 135 + 5000: (1455-455)+ax (40+ 4) = 272
o) 832: a + [40+ 8x (100:5-90:5)] × 10 = 592​