Question

thực hiện phép tính sau bằng cách hợp lý nhất :

a, ( 44. 52 . 60 ) : ( 11 . 13 . 15 )

b, ( 168 . 168 - 168 . 58 ) : 110

c, ( 27 .45 - 27 . 55 ) : ( 2 + 4 + 6 +...+ 18 )

help me

Answer 1

a) \\(\\dfrac{44.52.60}{11.13.15}=\\dfrac{4.11.4.13.4.15}{11.13.15}=4^3=64\\)

b) \\(\\dfrac{168.168-168.58}{110}=\\dfrac{168\\left(168-58\\right)}{110}=168\\)

c) Đặt \\(A=2+4+6+...+18\\)

\\(A=\\dfrac{\\left(2+18\\right).\\left(\\dfrac{18-2}{2}+1\\right)}{2}=\\dfrac{20.9}{2}=90\\)

=> Ta có: \\(\\dfrac{27.45-27.55}{2+4+6+...+18}=\\dfrac{27.\\left(-10\\right)}{90}=-3\\)