1) -6(2a-7)+4(5a-6) =-2 при a = -2,5
2a-7= -2,5*2-7=-5-7=-12 -6*(-12)= +72
5a-6= -2,5*5 -6= -12,5-6=-18,5 4*(-18,5) = -74
72+(-74)= - 2
2) -1,1(2m-4)-(2-3m)-0,4(1-m)=-0,8 при m=-4
2m-4= -4*2-4= -8-4=-12 -1,1*(-12)= + 13,2
2-3m= 2 -3*(-4)= 2+12=14
1-m= 1 -(-4)= 1+4=5 0,4*5=2
13,2-12 - 2= 13,2-14=-0,8
3)1 1/9 (3y-9)- 8 1/3(y-6)= -8 при y = 3.6
3y-9= 3*3.6=10.8= 10 8/10=10 4/5= 54/5
1 1/9*10.8= 10/9* 54/5=12
y-6= 3.6-6=-2.4= 2 4/10=2 2/5= 12/5
8 1/3= 25/3
25/3*12/5=20
12-20=-8