№4
а)х=65
б)8х=1,6
х=0,2
в)х=0.2
№1.
-9292 < -2929
№2.
-93 + 39 = -(93 - 39) = - 54
-64 - (-46) = - 64 + 46 = -(64 - 46) = - 18
85 * ( -104) = -8840
1272 : (-12) = -106
№3.
- 46*82 + 36*82 = 82 * (-46+36) = 82 * (-10) = -820
-846 +39 - (48-846) = -846 + 39 - 48 + 846 = -(48-39)=-9
№4.
(-240 : 5 - (32*4)) : (-16) =
= (- 48 - 128) : (-16) =
= -176 : (-16) = 11
№5.
48+2х=60
2х=12
х=6
х получился 6
Cos(a+b)/(sin(a)*sin(b))=(cos(a)*cos(b)-sin(a)*sin(b))/(sin(a)*sin(b))=
=cos(a)*cos(b)/(sin(a)*sin(b))-sin(a)*sin(b)/(sin(a)*sin(b))=ctg(a)*ctg(b)-1