Răspuns
Explicație pas cu pas:
5(x - 1) = x + 7
5x - 5 = x + 7
4x = 12
x = 3
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2(x + 3) - 5 = x - 7
2x + 6 - 5 = x - 7
2x + 1 = x - 7
x = -8
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2x + 5si2/3 = 2si1/4
2x = 9/4 - 17/3 = 27/12 - 68/12 = -41/12
x = -41/24
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4(x + 5) - 5(x + 3) = 6x - 5(x + 1)
4x + 20 - 5x - 15 = 6x - 5x - 5
-x + 5 = x - 5
2x = 10
x = 5
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(x+5)/3 + (2x +3)/4 = (x-5)/6 + 7/12
numitor comun este 12
4(x + 5) + 3(2x + 3) = 2(x - 5) + 7
4x + 20 + 6x + 9 = 2x -10 + 7
10x + 29 = 2x - 3
8x = -32
x = -4
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(x + 4)/5 - (x + 2)/3 = 2x/15 - (x + 1)/3
numitor comun este 15
3(x + 4) - 5(x + 2) = 2x - 5(x + 1)
3x + 12 -5x -10 = 2x -5x -5
-2x + 2 = -3x - 5
x = -7
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Prima zi: 10%
A doua zi: 30%
A treia zi: 42 km
In cele doua zile parcurge 10% + 30% = 40%
A treia zi: 100% - 40% = 60% = 42 km
Drumul are 42 x 100 / 60 = 70 km
(Verificare: 10% = 7 km; 30% = 21 km; 70 - 7 -21 = 42 km)
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Prima zi: 2S/5 + 300
Rest: S - 2S/5 - 300 = 5S/5 - 2S/5 - 300 = 3S/5 - 300
A doua zi: 2/3 * (3S/5 - 300) + 100
Rest
S - (2S/5 + 300) - {2/3 * (3S/5 - 300) + 100} = 2380
S - 2S/5 - 300 - (2S/5 - 200 + 100) = 2380
S - 2S/5 -300 -2S/5 + 200 - 100 = 2380
S - 4S/5 - 200 = 2380
5S/5 - 4S/5 = 2380 + 200
S/5 = 2580
S = 5 * 2580 = 12900
