A=3+32+38+32019
Cho A =32019:1+3+32+33+.......+32018 tìm A
A=32019+1+3+32+33+...+32018
⇒A=1+3+32+...+32018+32019
⇒3A=3×(1+3+3^2+3^3+....+3^2019)
3A=3+3^2+3^3+....+3^2020
3A-A=(3+3^2+3^3+....+3^2020) -(1+3+3^2+....+3^2019)
2A= 3^2020-1
⇒ A =( 3^2020-1):2
A=32019+1+3+32+33+...+32018
⇒A=1+3+32+...+32018+32019
⇒3A=3×(1+3+3^2+3^3+....+3^2019)
⇒3A=3+3^2+3^3+....+3^2020
⇒3A-A=(3+3^2+3^3+....+3^2020) -(1+3+3^2+....+3^2019)
⇒2A= 3^2020-1
⇒ A =( 3^2020-1):2
Cho A = 1 +3 + 32 + 33 + …..+ 32018 + 32019. Chứng tỏ rằng A ⋮ 4
\(A=1+3+3^2+3^3+...+3^{2018}+3^{2019}\)
\(=\left(1+3\right)+3^2\left(1+3\right)+...+3^{2018}\left(1+3\right)\)
\(=\left(1+3\right)\left(1+3^2+...+3^{2018}\right)\)
\(=4\left(1+3^2+...+3^{2018}\right)\) ⋮4
⇒A⋮4
Bài 4 : (0.5 điểm) Cho A = 1 +3 + 32 + 33 + …..+ 32018 + 32019. Chứng tỏ rằng A ⋮4
\(A=\left(1+3\right)+3^2\left(1+3\right)+...+3^{2018}\left(1+3\right)\)
\(=4\left(1+3^2+...+3^{2018}\right)⋮4\)
Chứng minh rằngA = 3 + 32+ 33+ ... + 32019+ 32020chia hết cho 10.
Ghi lại đề: \(A=3+3^2+...+3^{2020}\)
\(\Rightarrow A=\left(3+3^2+3^3+3^4\right)+...+\left(3^{2017}+3^{2018}+3^{2019}+3^{2020}\right)\\ A=3\left(1+3+3^2+3^3\right)+...+3^{2017}\left(1+3+3^2+3^3\right)\\ A=\left(1+3+3^2+3^3\right)\left(3+...+3^{2017}\right)\\ A=40\left(3+...+3^{2017}\right)⋮10\left(40⋮10\right)\)
Thu gọn C, biết :
C = 32023 - 32022 + 32021 - 32020 + 32019 - ... - 32 + 3.
Giúp mình với!
Viết các phép toán sau dưới dạng một lũy thừa với số mũ lớn hơn 1
a) 34 .275 . (32)3 | b) (23)4 .46 .32 |
c) 32019 .62019 : 2 2019 | d) 1258 . (52)4 |
a, 34.275.(32)3 = 34.(33)5.36 = 34.315.36 = 325
b, (23)4.46.32 = 212.212.25 = 229
c, 32019.62019: 22019 = 32019.32019.22019:22019 = (3.3)2019= 92019
d, 1258.(52)4 = (53)8.58 = 532
Tìm số tự nhiên x thỏa mãn 5.x−(32021−32019):32017=275.x−(32021−32019):32017=27.
Đáp số: x = .
Thực hiện phép tính:
(32021 + 24.32020) : 32019
\(\left(3^{2021}+24.3^{2020}\right):3^{2019}\)
\(=\left(3^{2021}:3^{2019}\right)+\left(24.3^{2020}:3^{2019}\right)\)
\(=3^2+24.3\)
\(=9+72=81\)
(3^2021+24.3^2020):3^2019
=(3^2021:32019)+(24.3^2020:3^2019)
=3^2+24.3
=9+72=81
Tính hợp lí (câu cuối rồi)
32019 : (32020 - 18 . 32017)
\(3^{2019}:\left(3^{2020}-18.3^{2017}\right)\)
\(=3^{2019}:\left[3^{2017}.\left(27-18\right)\right]\)
\(=3^{2019}:\left(3^{2017}.9\right)\)
\(=3^{2019}:\left(3^{2017}.3^2\right)\)
\(=3^{2019}:3^{2019}=1\)
giúp mình với , đang cần gấp !!!!!!!!!!!
b2
a) (38-60 ) + (20-38 )
b) 75-(20+75 )
c) 32+(60-32)
d) (81-36) - (81-36 )
e) (2+4+6+8) - (1+3+5+7)
f) (1+3+5+7+......+99) - (2+4+6+......+100)
chú ý : dạng quy tắc dấu ngoặc
a) (38 - 60) + (20 - 38)
= 38 - 60 + 20 - 38
= (38 - 38) + (-60 + 20)
= 0 - 40
= -40
b) 75 - (20 + 75)
= 75 - 20 - 75
= (75 - 75) - 20
= 0 - 20
= -20
c) 32 + (60 - 32)
= 32 + 60 - 32
= (32 - 32) + 60
= 0 + 60
= 60
d) (81 - 36) - (81 - 36)
= 81 - 36 - 81 + 36
= (81 - 81) + (-36 + 36)
= 0 + 0
= 0
e) (2 + 4 + 6 + 8) - (1 + 3 + 5 + 7)
= 2 + 4 + 6 + 8 - 1 - 3 - 5 - 7
= (2 - 1) + (4 - 3) + (6 - 5) + (8 - 7)
= 1 + 1 + 1 + 1
= 4
f) (1 + 3 + 5 + 7 + ... + 99) - (2 + 4 + 6 + 8 + ... + 100)
= 1 + 3 + 5 + 7 + ... + 99 - 2 - 4 - 6 - 8 - ... - 100
= (1 - 2) + (3 - 4) + (5 - 6) + (7 - 8) + ... + (99 - 100)
= -1 - 1 - 1 - 1 - ... - 1 (50 chữ số 1)
= -50