a) (7+12)-(5+20)= 19-25=-6
b)-3•[2-36:(-9)]-2•(6+8)= -3•(2+4)-2•14= -3•8-28= -24-28=-52
c)[(-5)^2 •(-5)^4 • (-5)^3]^5 : (-5)^43=
(-5)^ [(2+4+3)•5-43] = (-5)^ (9•5 -43) = (-5)^2= 25
d)(5-3)•3= 6
e) (-3-10):13+1=-1+1 =0
f)[|-9-27|+3+(-2)•(-2)]:(-3) = (36+3+4):3= 43:3= 14,2(6)