S = (a+b)•2
1 сторона - x
2 сторона - 5x
S = 84см
(x+5x)•2=84
6x•2=84
6x=84:2
6x=42
x=42:6
x=7
Значит 7см - 1 сторона, тогда 7•5=35см - 2 сторона.
Ответ: 7см, 35см.
х+5+х+5+х+5+х+5 = 4x + 20
x = - 16,35
4*(-16,35) + 20 = - 65,4 + 20 = - 45,4
15 * 3 = (10 + 5) * 3 = 10 * 3 + 5 * 3 = 30 + 15 = 45
17 * 3 = (10 + 7) * 3 = 10 * 3 + 7 * 3 = 30 + 21 = 51
4 * 14 = 4 * (4 + 10) = 4 * 4 + 4 * 10 = 16 + 40 = 56
7 * 13 = 7 * (10 + 3) = 7 * 10 + 7 * 3 = 70 + 21 = 91
43 * 5 = (40 + 3) * 5 = 40 * 5 + 3 * 5 = 200 + 15 = 215
33 * 6 = (30 + 3) * 6 = 30 * 6 + 3 * 6 = 180 + 18 = 198
3 * 48 = 3 * (40 + 8) = 3 * 40 + 3 * 8 = 120 + 24 = 144
7 * 27 = 7 * (20 + 7) = 7 * 20 + 7 * 7 = 140 + 49 = 189
28 * 3 = (20 + 8) * 3 = 20 * 3 + 8 * 3 = 60 + 24 = 84
39 * 3 = (30 + 9) * 3 = 30 * 3 + 9 * 3 = 90 + 27 = 117
6 * 86 = 6 * (80 + 6) = 6 * 80 + 6 * 6 = 480 + 36 = 516
9 * 37 = 9 * (30 + 7) = 9 * 30 + 9 * 7 = 270 + 63 = 333
120 * 4 = (100 + 20) * 4 = 100 * 4 + 20 * 4 = 400 + 80 = 480
140 * 5 = (100 + 40) * 5 = 100 * 5 + 40 * 5 = 500 + 200 = 700
320 * 4 = (300 + 20) * 4 = 300 * 4 + 20 * 4 = 1200 + 80 = 1280
460 * 2 = (400 + 60) * 2 = 400 * 2 + 60 * 2 = 800 + 120 = 920
9+4=13
13*2=26- первое
13+3=16
16*2=32-второе
36+1==37
37*2=74-третье
(18+2)*2=40-четвертое
(6+6)*2=24-пятое