a) ( x - 21 x13) : 11 = 39
b) ( x - 21) x 13 : 11 = 39
c) ( x - 5 ) x ( 2016 x 2017 + 2017 x 2018 ) = 1234 X 5678 x ( 636 -315 x 2) : 2018
Bài 1: Thực hiện các phép tính sau bằng cách thuận tiện nhất
a,9975 + 11970 + 13965 + 15960 + 17955 + 19950
b, 1234 x 5678 x [630 - 315 x2] :1996
c, 399 x 45 + 55 x 399
d,1996 x 1995 - 996 - 1000 - 1996 x 1994.
Bài 2: Tìm X :
a, ( X - 21 x 13) : 11=39
b,( X -21) x13:11=39
c, (18 x 38 + 16 x 76 - ) = ( 36 x 19 + 64 x20 - 65) x X
Ai tính nhanh mình cho 3 tích
1. Tìm x, biết :
a) 9 + x/ 15 - x = 5/7
b) x +x :5 * 9,5 + x : 4 * 10 = 315
2. Tính nhanh:
2018 *2017-1/2016*2018+201
Tìm giá trị nhỏ nhất
P = 2018/x^2+2x+2017
Q = a^2018+2017/a^2018+2015
A = (x-3y)^2020+(y-2018)^2018
B = (x+y-5)^8+(x-2y)^4+2016
C = \x-2017\+\x-2018\
D = \x-2010\+\x-2011\+\x+2012\
1. Cho biểu thức B :
\(B=x^{2017}-2018.x^{2016}+2018.x^{2015}-2018.x^{2014}+...-2018.x^2+2018.x-1\)
TÍNH GIÁ TRỊ BIỂU THỨC VỚI x=2017
3. Cho : \(\frac{xy+1}{9}=\frac{yz+2}{15}=\frac{xz+3}{27}\)và xy +yz + zx=11 . TÌM x,y,z
a)\(\frac{x+2015}{5}+\frac{x+2016}{4}=\frac{x+2017}{3}+\frac{x+2018}{2}\)
b)\(\frac{x+2015}{5}+\frac{x+2016}{6}=\frac{x+2017}{7}+\frac{x+2018}{8}\)
a) \(\frac{x+2015}{5}+\frac{x+2016}{4}=\frac{x+2017}{3}+\frac{x+2018}{2}\)
\(\Leftrightarrow\frac{x+2015}{5}+\frac{5}{5}+\frac{x+2016}{4}+\frac{4}{4}=\frac{x+2017}{3}+\frac{3}{3}+\frac{x+2018}{2}+\frac{2}{2}\)
\(\Leftrightarrow\frac{x+2020}{5}+\frac{x+2020}{4}=\frac{x+2020}{3}+\frac{x+2002}{2}\)
\(\frac{x+2020}{5}+\frac{x+2020}{4}-\frac{x+2020}{3}-\frac{x+2020}{2}=0\)
\(\Leftrightarrow\left(x+2020\right).\left(\frac{1}{5}+\frac{1}{4}-\frac{1}{3}-\frac{1}{2}\right)=0\)
\(\Leftrightarrow x+2020=0\)
\(\Leftrightarrow x=-2020\)
Vậy : \(x=-2020\)
Chúc bạn học tốt !!
a) \(\frac{x+2015}{5}+\frac{x+2016}{4}=\frac{x+2017}{3}+\frac{x+2018}{2}\\ \left(\frac{x+2015}{5}+1\right)+\left(\frac{x+2016}{4}+1\right)=\left(\frac{x+2017}{3}+1\right)+\left(\frac{x+2018}{2}+1\right)\\ \frac{x+2020}{5}+\frac{x+2020}{4}=\frac{x+2020}{3}+\frac{x+2020}{2}\\ \frac{x+2020}{5}+\frac{x+2020}{4}-\frac{x+2020}{3}-\frac{x+2020}{2}=0\\ \left(x+2020\right)\left(\frac{1}{5}+\frac{1}{4}-\frac{1}{3}-\frac{1}{2}\right)=0\\ \Rightarrow x+2020=0\\ \Rightarrow x=-2020\)
Vậy x = -2020
b) \(\frac{x+2015}{5}+\frac{x+2016}{6}=\frac{x+2017}{7}+\frac{x+2018}{8}\\ \left(\frac{x+2015}{5}-1\right)+\left(\frac{x+2016}{6}-1\right)=\left(\frac{x+2017}{7}-1\right)+\left(\frac{x+2018}{8}-1\right)\\ \frac{x+2010}{5}+\frac{x+2010}{6}=\frac{x+2010}{7}+\frac{x+2010}{8}\\ \frac{x+2010}{5}+\frac{x+2010}{6}-\frac{x+2010}{7}-\frac{x+2010}{8}=0\\ \left(x+2010\right)\left(\frac{1}{5}+\frac{1}{6}-\frac{1}{7}-\frac{1}{8}\right)=0\\ \Rightarrow x+2010=0\\ \Rightarrow x=-2010\)
Vậy x = -2010
tìm x . 0.05*((2x-2)/2016 +2x/2017+(2x+2)/2018)=3.3-((x-1)/2016+x/2017+(x+1)/2018)
Tìm N(2017) biết đa thức N(x)=\(x^{2017}-2018.x^{2016}+2018.x^{2015}-2018.x^{2014}+........-2018.x^2+2018.x-1\)
Ta có: \(N\left(x\right)=x^{2017}-2018x^{2016}+2018x^{2015}-...-2018x^2+2018x-1\)
\(=x^{2017}-2018\left(x^{2016}-x^{2015}+...+x^2-x\right)-1\)
\(\Rightarrow N\left(2017\right)=2017^{2017}-2018\left(2017^{2016}-2017^{2015}+...+2017^2-2017\right)-1\)
Đặt \(A=2017^{2016}-2017^{2015}+...+2017^2-2017\)
\(\Rightarrow2017A=2017^{2017}-2017^{2016}+...+2017^3-2017^2\)
\(\Rightarrow2018A=2017^{2017}-2017\)
\(\Rightarrow A=\dfrac{2017^{2017}-2017}{2018}\)
\(\Rightarrow N\left(2017\right)=2017^{2017}-2018.\dfrac{2017^{2017}-2017}{2018}-1\)
\(=2017^{2017}-\left(2017^{2017}-2017\right)-1\)
\(=2017^{2017}-2017^{2017}+2017-1\)
\(=2016\)
Vậy N(2017) = 2016
( 2016 x 2017 + 2018 x 2 + 2015 ) : [ ( 2018 : 2017 - 2017 x 2015 ) + 2016 ]
Tính nhanh nhé!
Các bạn làm giúp mình với sao từ nãy giờ chẳng có ai giúp mình vậy?Để mình gợi ý cho các bạn một tí thôi nhé,nhớ giúp mình đấy.
Đáp án là : -1,002482622
Ai có cùng đáp án là làm đúng rồi đấy nếu đúng thì hãy chia sẻ cách làm của các bạn với mình nhé.
a) 13 (x - 9 ) = 169
b) 7^x+2 =243
c) 230 + [ 16+ (x-5)] =315 .2^3
d) 13. x - 3^2 .x = 2017^1 - 1^2018
e) (3 x + 1)^5 = 1024
a,
13[x-9] = 169
=> x - 9 = 169/13
=> x - 9 = 13
=> x = 13+9
=> x = 22
b,
Viết lại đề:
7x+3 = 343
<=> 7x+3 = 73
=> x + 3 = 3
=> x = 3-3
=> x = 0
c,
230 + [16 + [x-5]] = 315 . 23
=> 230 + [16 + x - 5] = 315 . 8
=> 230 + 16 + x - 5 = 2520
=> 230 + 16 + x = 2520 + 5 = 2525
=> x = 2525 - 230 - 16 = 2279
d,
13.x - 32.x = 20171 - 12018
=> 13x - 9x = 2017 - 1
=> 4x = 2016
=> x = 504
a) 13 ( x-9 )=169
=> x-9 =169 : 13 =13
=> x=13+9 =22
b)\(7^{x+3}=343\)
\(7^x.7^3=343\)
\(7^x=343:7^3\)
\(7^x=1\Rightarrow x=1\)
c)230 + 16 +x -5 =315.8
241 +x =2520
x=2520-241=2279
d) 13x -\(3^2.x\)=2017-1
x(13-9)=2016
x.4=2016
x=2016:4
x=504