(-17).39+17.(-161)
a) 83 - (-756 - 17) + (50 - 756)
b) -105 + (-34 - 95) - 166
c) -(39 + 228 - 407) + (118 - 161)
d) 5^10 : 5^8 + 60 : 12 + (-10)
e) -342 - (161 - 342) - 39
g) 7^5 : 7^3 + (-187 - 149) - 213
Câu a, b, c, e bạn áp dụng quy tắc đấu ngoặc để mở ngoặc rồi tính
Câu d, g bạn tính như bình thường
a) 83 - (-756 - 17) + (50 - 756)
b) -105 + (-34 - 95) - 166
c) -(39 + 228 - 407) + (118 - 161)
d) 5^10 : 5^8 + 60 : 12 + (-10)
e) -342 - (161 - 342) - 39
g) 7^5 : 7^3 + (-187 - 149) - 213
\(a.83-\left(-756-17\right)+\left(50-756\right)=83+756+17+50-756=\left(83+17\right)+50+\left(756-756\right)=100+50=150\)
\(b.-105+\left(-34-95\right)-166=-105+\left(-34\right)-95-166=\left(-105-95\right)-\left(34+166\right)=\left(-200\right)-200=-400\)
\(c,-\left(39+228-407\right)+\left(118-161\right)=-39-228+407+118-161=\left(-39-161\right)-\left(228-118\right)+407=\left(-200\right)-110=-310\)
\(d,5^{10}:5^8+60:12+\left(-10\right)=5^2+5+\left(-10\right)=5\left(5+1-2\right)=5.4=20\)
\(e,-342-\left(161-342\right)-39=-342-161+342-39=\left(-342+342\right)-\left(161+39\right)=-200\)\(g,7^5:7^3+\left(-187-149\right)-213=7^2+\left(-187\right)-149-213=\left(49-149\right)-\left(187+213\right)=\left(-100\right)-400=-500\)
Bài 1:Tính hợp lí (nếu có thể)
a) -19+84+19+16
b) (437-25)-(175+437)
c) 23 .(-7).125
d) (-17).39+17.(-161)
a)\(\text{ -19+84+19+16 }\)
\(=\left(-19+19\right)+\left(84+16\right)\)
\(=0+100=100\)
\(\left(437-25\right)-\left(175+437\right)\)
\(=437-437-\left(25+175\right)=-200\)
\(c\))\(2^3.\left(-7\right).125\)
\(=\left(8.125\right).\left(-7\right)\)
\(=1000.\left(-7\right)=-7000\)
a). -19+84+19+16= 19+ (-84) +19+16= 19+ ( -84 + 16) = 19 + (-68 )= - 49
c). 23. (-7) . 125 = 8. (-7) . 125 = (125.8). (-7) = 1000. (-7 ) = -7000
d). (-17) . 39 + 17.( -161) = 17. (-39 ) + 17. (-161) = 17. \([\left(-39\right)+\left(-161\right)]\) = 17. (-200)= -3400
nhớ k cho mik nha <3
(17-3x)^3+36=161
\(\left(17-3x\right)^3+36=161\)
=> \(\left(17-3x\right)^3=161-36=125\)
=> \(\left(17-3x\right)^3=5^3\)
=> \(17-3x=5\)
=> \(3x=12\)
=> \(x=4\)
What is the next number in the sequence: 1, 5, 17, 53, 161, ... ?
We have: 1 . 3 + 2 = 5
5 . 3 + 2 = 17
17 . 3 + 2 = 53
53 . 3 + 2 = 161
=> The next number in the sequence is: 161 . 3 + 2 = 485
Tính nhanh: 17×17+17×44+39×17
\(17\times17+17\times44+39\times17=17\left(17+44+39\right)\)
\(=17\times100=1700\)
17x17+17x44+39x17
= 17x(17+44+39)
= 17x(100)
=1700
17 x 17 + 17 x 44 + 39 x 17
= 17 x ( 17 + 44 + 39)
= 17 x 100
=1700
Giai pt:
x-241/17+x-220/19+x-195/21+x-161/23=10
\(\dfrac{x-241}{17}+\dfrac{x-220}{19}+\dfrac{x-195}{21}+\dfrac{x-161}{23}=10\)
<=>\(\dfrac{x-241}{17}-1+\dfrac{x-220}{19}-2+\dfrac{x-195}{21}-3\dfrac{x-161}{23}-4=0\)
<=>\(\dfrac{x-258}{17}+\dfrac{x-258}{19}+\dfrac{x-158}{21}+\dfrac{x-158}{23}=0\)
<=>\(\left(x-258\right)\left(\dfrac{1}{17}+\dfrac{1}{19}+\dfrac{1}{21}+\dfrac{1}{23}\right)=0\)
vì 1/17+1/19+1/21+1/23 khcas 0
=>x-258=0<=>x=258
vậy...............
chcus bạn học tốt ^^
1, Thực hiện phép tính
A=2-5+8-11+14-17...+158-161+164
Tìm x :
a) 7.x -x = 5²¹ : 5 mũ 19 + 3.2² - 7 mũ 0 .
b) 7. x - 2.x = 6 mũ 17 : 6 mũ 15 + 44 :11
c) 5.x + x = 39 - 3 ¹¹ : 3 mũ 9
d) [(6.x -39): 7] . 4 = 12
So sánh :
13 mũ 40 và 2 mũ 161
a) 7.x - x = 521 : 519 + 3.22 - 70
6x = 25 + 12 - 1
6x = 36
x = 6
b) 7x - 2x = 617 : 615 + 44 : 11
5x = 36 + 4
5x = 40
x = 8
c) 5x + x = 39 - 311 : 39
6x = 39 - 9
6x = 30
x = 5
d) [(6x - 39) : 7]. 4 = 12
(6x - 39) : 7 = 12 : 4
(6x - 39) : 7 = 3
6x - 39 = 3 . 7
6x - 39 = 21
6x = 21 + 39
6x = 60
x = 10
x =