9.
6.4-2x=14
-2x=14-6.4
-2x=7.6
I 6.4+7.6 I=14
5.
-3(5х-4)+2(х+4)= -6
-15х+12+2х+8= -6
-13х= -6-12-8
13х=26
х=2
6,
0,75*( -1 1/3)*( -0,02)*50= 3/4*4/3*1=1
III.
7.
-2 2/3+2 1/3*(-15 2/7-(-4.8):4/15)= -8/3+7/3*(-15 2/7+24/5*15/4)= -8/3+7/3*(-15 2/7+18)= -8/3+7/3 * 19/7= -8/3+19/3=11/3=3 2/3
8,
1,5(-2,4a+3.8b)-1.6(2.5a-b)= -3.6a+5.7b-4a+1.6b= -7.6a+7.3b
при a=2, b= -3
-7.6*2-7.3*3= -15.2-21.9= - 37.1
IV
9.
I 7.8--0.4xI=4
0.4х=7,8-4
0,4х=3,8
I 7.8-3.8 I=4