(-3).122+(-3).77+(-3)
286 - { 122 + 77 - ( 12 + 21 ) }
286 - { 122 + 77 - ( 12 + 21 ) }
=286 - { 122 + 77 - 33 }
=286 - {199-33}
=286 - 166=120
286 - { 122+77- (12 + 21) }
=286 - {122 + 77 - 33}
= 286 - 166
= 120
286 - { 122 + 77 - ( 12 + 21 ) }
= 286 - { 122+77 - 33 }
= 286 - { 199 -33 }
= 286 - 166
= 120
Tính nhanh: 3/1x2+3/2x3+3/3x4+3/4x5+3/5x6+...+3/9x10+77/2x9+77/9x16+77/16x23+...+77/93x100
Giúp mình với nhé!
=3.(1/1.2+1/2.3+....+1/9.10)+11.(1/2.9+1/9.16+...+1/93.100)
=3.(1-1/2+1/2-1/3+1/3 - ... - 1/10)+11.(1/2-1/9+1/9-...-1/100)
= 3.(1-1/10) + 11.( 1/2-1/100)
= 3. 9/10+11.49/100
chỗ này bạn tự tính máy tính nha
bn ơi cho mình hỏi dấu chấm là chia à
122+132=?
33+33=?
Tính nhanh
12*23+12*77
122 + 132 = 254
33 + 33 = 33 x 2 = 66
tính nhanh
12 x 23 + 12 x 77
= 12 x (23 + 77)
= 12 x 100
= 1200
122 + 132 = 254
33 + 33 = 66
12 x 23 + 12 x 77
= 12 x (23 + 77)
= 12 x 100
= 1200
3/5*8 + 3/8*11 + 3/11*14 +....+3/119*122
(Dấu . là dấu nhân)
\(\dfrac{3}{5.8}+\dfrac{3}{8.11}+\dfrac{3}{11.14}+...+\dfrac{3}{119.122}\)
\(=\dfrac{1}{5}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{11}+\dfrac{1}{11}-\dfrac{1}{14}+...+\dfrac{1}{119}-\dfrac{1}{122}\)
\(=\dfrac{1}{5}-\dfrac{1}{122}\)
\(=\dfrac{122}{610}-\dfrac{5}{610}\)
\(=\dfrac{117}{610}\)
#Sahara |
\(\dfrac{3}{5.8}+\dfrac{3}{8.11}+\dfrac{3}{11.14}+.....+\dfrac{3}{119.122}\)
\(=\dfrac{1}{5}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{11}+\dfrac{1}{11}-\dfrac{1}{14}+......+\dfrac{1}{119}-\dfrac{1}{122}\)
\(=\dfrac{1}{5}-\dfrac{1}{122}=\dfrac{122-5}{610}=\dfrac{117}{610}\)
A = 3/1 x 2 + 3/2 x3 + 3/3 x 4 + 3/4 x 5 + .............. + 3/9 x 10 + 77/2 x 9 + 77/9 x 6 + 77/16 x 23 + ...............+ 77 /93x 100
Giup mk nha!!!!!!! Ban nao tra loi nhanh thi mk tk cho nha!!!!!!!!! >-<
SO SÁNH : A = 3^123 +1 / 3^125 + 1 và B = 3^122/ 3^124 + 1
A = \(\dfrac{3^{123}+1}{3^{125}+1}\) Vì 3123 + 1 < 2125 + 1 Nên A = \(\dfrac{3^{123}+1}{3^{125}+1}\)< \(\dfrac{3^{123}+1+2}{3^{125}+1+2}\)
A < \(\dfrac{3^{123}+3}{3^{125}+3}\) = \(\dfrac{3.\left(3^{122}+1\right)}{3.\left(3^{124}+1\right)}\) = \(\dfrac{3^{122}+1}{3^{124}+1}\) = B
Vậy A < B
Tìm x:
1. x(2x-3) - 2x^2 =12
2. 2x(x-3) - 4(x-3)=0
1. \(\Leftrightarrow2x^2-3x-2x^2=12\\ \Leftrightarrow-3x=12\\ \Leftrightarrow x=-4\)
2. \(\Leftrightarrow\left(2x-4\right)\left(x-3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=2\\x=3\end{matrix}\right.\)
1) \(\Rightarrow2x^2-3x-2x^2=12\Rightarrow-3x=12\Rightarrow x=-4\)
2) \(\Rightarrow2\left(x-3\right)\left(x-2\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=3\\x=2\end{matrix}\right.\)
So sanh A = 3^123+1/3^125+1 va B= 3^122+1/3^124+1
SO SÁNH A = 3^123 + 1 / 3^125 + 1 và B = 3^122+1 / 3^124+1
SO SÁNH : A = 3^123 +1 / 3^125 + 1 VÀ B = 3^122 + 1 / 3^124 + 1