Ответ:
а) 2х = 4/7
х = 4/7 * 1/2
х = 2/7
б) -10z = 2/5
z = -2/5 *1/10
z = - 1/5 * 1/5
z = - 1/25
в) 3х = -1/3
х = - 1/3 * 1/3
х = -1/9
А) 1 2/5+0,52=1,4+0,52=1,92
Б)4/7-0,4=4/7-2/5=20/35-14/35=6/35
В)2,5:1 2/3=5/2*3/5=3/2=1,5
Г)1 1/15+1,15=1 1/15+1 3/20=1 4/60+
1 9/60=2 13/60
Д)4 11/16-2,729=4,6875-2,729=1,9585
Е) 1 2/7*3,5=9/7*7/2=9/2=4,5
<span>(5/8 - 2/5) + 3/20=</span>
<span>5/8-2/5+3/20= (25-16+6)/40=15/40=3/8</span>
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<span><span>1/8 +(5/9 -1/4)=1/8+5/9-1/4=(9+40-18)/72=31/72</span></span>