Explicație pas cu pas:
a)
5 × (24 × 17 + 52 × 25 - a) = 0
5 × (408 + 1300 - a) = 0
5 × (1708 - a) = 0 |:5
1708 - a = 0
1708 = a
a = 1708
b)
18 × 3 + b × [(72 - 5 × 12) - 2] =
54 + b × [(72 - 60) - 2] =
54 + b × (12 - 2) =
54 + b × 10 =
c)
c - [24 × 48 - 20 × (52 - 47)] = 297
c - (1152 - 20 × 5) = 297
c - (1152 - 100) = 297
c - 1052 = 297
c = 297 + 1052
c = 1349
d)
12 × 25 × 5 - 2 × (d + 4) = 240
300 × 5 - 2 × (d + 4) = 240
1500 - 2 × (d + 4) = 240
1500 = 240 + 2 × (d + 4)
1500 - 240 = 2 × (d + 4)
1260 = 2 × (d + 4) |:2
630 = d + 4
630 - 4 = d
d = 630 - 4
d = 626
==pav38==