21 = 7 * 3
18 = 2 * 3 * 3 = 2 * 3²
НОК (21 и 18) = 7 * 2 * 3² = 14 * 9 = 126
24 = 3 * 2³
32 = 7 * 2²
НОК (24 и 32) = 3 * 7 * 2³ = 21 * 8 = 168
16 = 2⁴
20 = 5 * 2²
НОК (16 и 20) = 2⁴ * 5 = 16 * 5 = 80
20 = 5 * 2²
35 = 5 * 7
НОК (20 и 35) = 5 * 7 * 2² = 35 * 4 = 140
75 = 3 * 5²
90 = 2 * 3 * 3 * 5 = 2 * 5 * 3²
НОК (75 и 90) = 5² * 3² * 2 = 25 * 9 * 2 = 450
6 = 2 * 3
13 = 13 * 1
НОК (6 и 13) = 6 * 13 = 78
14 = 2 * 7
18 = 2 * 2 * 3 = 2² * 3
НОК (14 и 18) = 2² * 7 * 3 = 4 * 21 = 84
28 = 7 * 2²
42 = 7 * 2 * 3
НОК (28 и 42) = 7 * 2² * 3 = 21 * 4 = 84
21 = 7 * 3
33 = 3 * 11
НОК (21 и 33) = 7 * 3 * 11 = 7 * 33 = 231
12 = 2 * 2 * 3 = 2² * 3
30 = 2 * 3 * 5
75 = 3 * 5²
НОК (12, 30 и 75) = 2² * 3 * 5² = 4 * 3 * 25 = 12 * 25 = 300
15 = 3 * 5
42 = 7 * 2 * 3
105 = 3 * 5 * 7
НОК (15, 42 и 105) = 3 * 5 * 2 * 7 = 210
21 = 3 * 7
28 = 2² * 7
35 = 5 * 7
НОК (21,28 и 42) = 7 * 3 * 5 * 2² = 420
0,4√2500-1/3√81=0,4*50-1/3*9=20-3=17
В=а+30=65+30=95
в=а+30=100+30=130
<span>а)2,1x-3,5=1,4x
2,1x-1,4x=3,5
0,7x=3,5</span>
x=3,5/0,7
x=5
б)2(4-1,9х)=0,8х-0,2
8-3,8x=<span>0,8х-0,2
-3,8x-</span>0,8х=-8-<span>0,2
-4,6x=-8,2
x=</span>-8,2/<span>-4,6
x=1,78
</span>