Question

Aflati x din egalitatile : 

a) ( 256 + 3 X + 2 X ) ori 12 = 4272

b) [(X- 28 ori 2) ori 3 + 5 ] ori 12 = 1644 

c) 100 ori [ 25 - 5 ori ( X - 3 ) + 2 ] : 4 = 300

Answer 1

 ( 256 + 3 X + 2 X ) ori 12 = 4272
12(256+5x)=4272
3072+60x=4272
60x=4272-3072
6x=1200
x=1200:6
x=200

b) [(X- 28 ori 2) ori 3 + 5 ] ori 12 = 1644 
[(x-56)·3+5]·12=1644:12
[(3x-168)+5]=137
3x-168=137-5
3x-168=132
3x=132+138
3x=270
x=270/3
x=90

c) 100 ori [ 25 - 5 ori ( X - 3 ) + 2 ] : 4 = 300
100[25-5x+15+2]:4=300
100·[37-5x]:4=300
3700-500x=300·4
500x=3700-1200
500x=2500
x=2500/500
x=5