#2
x+3/4x+2(10+x)+4=-6
1 3/4x+20+2x=-6-4
3 3/4x=-10-20
3 3/4x=-30|: 3 3/4
x=-30*4/15=-8
#3
15*(-m³)⁴*2/3*(-a²)^6*b=15*m^12*2/3*a^12*b=10m^12a^12b
#4
-25/36*(-1 1/5)³*(-5)²=-25/36*(-216/125)*25=6/5*25=30
#5
(1/3)²:(-1/3)³=1/9:(-1/27)=-3
#6
7=5x-10
-5x=-10-7
-5x=-17|:(-5)
x=3,4
#7
-3=1*12+m
-m=12+3|:(-1)
m=-15
y=12x-15
#9
y=3x-3
3-(-3)=6
#10
(2a²c)³*(-0,5a³c)²=8a^6c³*0,25a^6c²=
2a^12c^5