[tex]\bold{b)} \ 7 *7^{23}:7^{24}=7^{24}:7^{24}=1; \\ \bold{c)} \ 11^{50}-11*11^{49}=11^{50}-11^{50}=0; \\ \bold{d)} \ 2^{17}*2^{18}-2^{34}*2=2^{17+18}-2^{34+1}=2^{35}-2^{35}=0; \\ \bold{e)} \ (29-2*7)^2*15^{20}-15^{22}=15^{2}*15^{20}-15^{22}=15^{2+20}-15^{22}=0; \\ \bold{f)} \ (12-3)^2*(6+3)^{18}-9^{20}=9^2*9^{18}-9^{20}=9^{2+18}-9^{20}=0; \\ \bold{g)} \ (4^2:2^2)^2*4^{18}:256^5=4^2*4^{18}:(4^4)^5=4^{20}:4^{20}=1.[/tex]
