AB^2=(9-2)^2+(10-3)^2+(-5-(-5))^2=98
AB=√98
AC^2=(9-2)^2+(3-3)^2+(2-(-5))^2=98
AC=√98
BC^2=(2-2)^2+(10-3)^2+(2-(-5))^2=98
BC=√98
AB=AC=BC=√98 => треугольник равносторонний
.....................................................................
1)(43-39)•x=24
4x=24
x=24:4
x=6
2)12:x+10=13
12:x=13-10
12:x=3
x=12:3
x=4
1) =1
2)=-0,5
вроде правельно