/x - 2017 / + /x - 2018 / +/ x - 2019 /
a.1/3 x 2019/2020
b. 2017 x 2018/2019 x 2019/2018
Cho x,y là số thục biết x^2016 +y^2016= x^2017 + y^2017= x^2018 +y^2018. Tính x^2019 + y^2019
x2019-2019.x2018+2019.x2018+2019.x2017-2019.x2016+......2019.x-200
Giúp mik vs nhé
x2019-2019.x2018+2019.x2018+2019.x2017-2019.x2016+......2019.x-200 Tại x=2018
Giúp mik vs nhé
Sai đề nên t sửa luôn nhé!
Vì \(x=2018\Rightarrow2019=2018+1=x+1\)
\(A=x^{2017}-2019\cdot x^{2018}+2019\cdot x^{2017}-2019\cdot x^{2016}+....+2019\cdot x-200\)
\(\Rightarrow A=x^{2019}-\left(x+1\right)x^{2018}+\left(x+1\right)x^{2017}-\left(x+1\right)x^{2016}+....-\left(x+1\right)x^2+\left(x+1\right)x-200\)
\(\Rightarrow A=x^{2019}-x^{2019}-x^{2018}+x^{2018}+x^{2017}-x^{2017}-x^{2016}+....-x^3-x^2+x^2+x-200\)
\(\Rightarrow A=x-200=2018-200=1818\)
B=x^2020 -2019 x^2019 - x^2018 - 2019 x^2017 - ...-2019x-2020 với x=2020
tính nhanh: 26 x 84+74 x 85
2017 x 2018 +2019/ 2019 x 2018 - 2017.
giải đầy đủ, ai nhanh nhất mk tick, 3 cái luôn
26 x 84 + 74 x 85
= 26 x 84 + 74 x 84 + 74
= 84 x (26 + 74) + 74
= 84 x 100 + 74
= 840 + 74
= 914
\(\frac{2017\times2018+2019}{2019\times2018-2017}\)
= \(\frac{2019\times2018-2\times2018+2019}{2019\times2018-2017}\)
= \(\frac{2019\times2018-4036+2019}{2019\times2018-2017}\)
= \(\frac{2019\times2018-2017}{2019\times2018-2017}\)
= 1
Dùng máy tính đó
Hoặc động cái não mà nghĩ đi với
tính nhanh: 26 x 84+74 x 85
2017 x 2018 +2019/ 2019 x 2018 - 2017.
giải đầy đủ, ai nhanh nhất mk tick, 3 cái luôn.
26x84+74x85=8474
2017x2018+2019/2019x2018-2017=4070307
câu trả lời đấy cu
So sánh A và B
a ) A = 2018 x 2018 ; B = 2017 x 2019
b) A= 2018 x 2019 ; B = 2017 x 2020
c ) A = 32 x 53 - 31 ; B = 53 x 31 - 32
a/ \(A=2018\cdot2018\)
\(=\left(2019-1\right)\cdot2018=2019\cdot2018-2018\)
\(B=2017\cdot2019\)
\(=\left(2018-1\right)\cdot2019=2018\cdot2019-2019\)
\(\Rightarrow A>B\)
b/
\(A=2018\cdot2019\)
\(=\left(2017+1\right)\cdot2019=2017\cdot2019+2019\)
\(B=2017\cdot2020\)
\(=2017\cdot\left(2019+1\right)=2017\cdot2019+2017\)
\(\Rightarrow A>B\)
Quên câu cuối ạ
c/ \(A=32\cdot53-31\)
\(=32\cdot53-32+1\)
\(B=53\cdot31-32\)
\(=53\cdot\left(32-1\right)-32=32\cdot53-32-53\)
có 1 > (-53)
\(\Rightarrow A>B\)
a) A > B
b) A > B
c) A > B
( 2019 . x - 2019 ) . (2019 . 2018 -2017 )
tìm x
Tính nhanh :
a,2017 x 2021 - 4031 / 2020 + 2017 x 2018
b,2017 x 2019 + 1009 / 2019 x 4035 - 1
Cho x,y>0 thỏa mãn
x^2015+y^2015=x^2016+y^2016=x^2017+y^2017
C/m: 1/x^2018+1/y^2018=1/x^2019+1/y^2019