X-45=38
x=45+38
x=83
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83-45=38
2 3/4+(-2/5+1 1/2)-(3/4-5/6)+3 1/6=11/4:(-2/5+3/2)-(19/12):19/6=11/4:11/10+19/12*6/19=11/4*10/11+1/2=1/2*5+1/2=5/2+1/2=3
0,6(у-3)-0,5(у-1)=1,5
0,6у-1,8-0,5у+0,5=1,5
0,6у-0,5у=1,5+1,8-0,5
0,1у=2,8
у=2,8/0,1
у=28
ответ 28
1) 2 5/7 - 1.3/5 =19/7 - 8/5 = (19*5 -8*7)/35 = 39/35
2) 39/35 : 1,3 =39/35 * 10/13= ( 39*10) / (35 * 13) =(3 *2) /(7*1) = 6/7
3) 1. 3/7 * 0,25 = 10 /7 * 1/4 = 10/28 = 5/14
4) 6/7 - 5/14 =( 6*2 -5)/14 = 7/14 =1/2
5)( 2/5 -7/18) * 15 = (2/5 * 15 ) - (7/18 *15) = ((2*15)/5 ) - ((7*15)/18) =
= 6- (35 /6) = 6 - 5.5/6 = 1/6
6) 1/2 : 1/6 =1/2 * 6/2 = 6/2 =3