Question

[Dương Ngọc Minh Châu]

B1) Tinh

a) 245-4 . [15: 8 +2.(4+3 mu 2 -9)]
 

b) 375: 5 mu 3 -( 3 mu 8: 3 mu 6 -2 .2 mu 3)

B2: Tim x

a) 2x -2 mu 3 .3 mu 2=138

b) ( 6x- 3 mu 4) . 7 mu 3= 3 . 7 mu 4

c) 1+2+3+..............+x =500500

Answer 1

[Nguyễn Ngọc Bảo Thi]

Bài 2 A,2x-2^3.3^2=138 2x-8.9 =138 2x-72 =138 2x =138+72 2x =210 x =210:2 x =105 b,(6x-3^4).7^3=3.7^4 (6x-81).343 =3.2401 (6x-81).343 =7203 (6x-81) =7203:343 (6x-81) =21 6x =21+81 6x =102 x =102:6 x =17