a) (-1584):(-2)^2-[126-(-3^2).(-2)^3]
Bài 2 Tính nhanh:
(1)1. 1 + (-1)2.2 + (-1)3.3 + .... + (-1)2020.2020
1572 – (17 – 3726) – (3726 + 1584)
149 – (127 – 51) + 35 – (73 + 235)
(-27).18 – 12.(-54)
(-43). (55 – 81) + 55.(43 – 81)
Tính giá trị của các biểu thức sau:
1)A= (2011^3 - 1)/(2011^2+2012)
2) B= 126^2-52*126+26^2
A=126/{60/[(\(3^2+4^2\))-5]}
\(A=120:\left\{60:\left[\left(3^2+4^2\right)-5\right]\right\}\)
\(A=120:\left\{60:\left[\left(9+16\right)-5\right]\right\}\)
\(A=120:\left\{60:\left[25-5\right]\right\}\)
\(A=120:\left\{60:20\right\}\)
\(A=120:3\)
\(A=40\)
Tính nhanh:
a) 153^2+99×153+47^2.
b) 126^2-152×126+5776.
c) 3^8×5^8-(15^4-1)×(15^4+1).
d) (2+1)×(2^2+1)×(2^4+1)...(2^32+1)+1
Ai giúp mình làm bài này với. Mình cảm ơn nhiều.
a) 153^2+99.153+47^2
= 153^2+2.47.153+47^2
= (153+47)^2
=200^2
=40000
b) 126^2-152.126+5776
= 126^2-2.76.126+76^2
= (126-76)^2
= 50^2
= 2500
c)3^8.5^8-(15^4-1).(15^4+1)
= 15^8-[(15^4)^2-1^2]
= 15^8-15^8+1
=1
d) (2+1).(2^2+1).(2^4+1)...(2^32+1)+1
= 1.(2+1).(2^2+1).(2^4+1)...(2^32+1)+1
= (2-1).(2+1).(2+1).(2^4+1)...(2^32+1)+1
= (2^2-1).(2^2+1).(2^4+1)...(2^32+1)+1
= (2^4-1).(2^4+1)...(2^32+1)+1
= (2^8-1)...(2^32+1)+1
= (2^32-1).(2^32+1)+1
= 2^64-1+1
= 2^64
cho A=1/2+2/8+3/28+4/77+5/176 và B=3/54+5/126+7/294+8/609.Tính A/B
Bài 1:Tính nhanh
A=21.72 -11.72 + 90.72+49.125.16
B=(1262+1263):1262
C=-(-225)+178-46+(-154)-(-22)
Tìm x :
a. 3 . 3^x = 126
b. 5^x + 5^x+2 = 650
c. 720 : [41 - (2x-5)] = 2^3 . 5
giúp mik với
mik cần gấp
1) Cho A=4+4^2+2^4+...+2^20.Hỏi A có chia hết cho 128 ko ?
2) Cho S =5+5^2+5^3+...+5^2006.
a) Tính S
b) Chứng minh: S chia hết cho 126 .
4) Cho C =3+3^2+3^3+3^4+....+3^300.Chứng tỏ C chia hết cho 40
cho 2 so co tong 54 neu gap so nho ben phai so lon va so lon ghep ben phai so nho ta duoc 2 so co 4 chu so hieu chung la 1584 tim 2 so do
a/ 5x+3 +5x=126
\(\dfrac{9-3x}{2}=\dfrac{5-2x}{3}\)
c/ 7-4(x+1)=5
a) \(5^{x+3}+5^x=126\)
\(\Rightarrow5^x\cdot\left(5^3+1\right)=126\)
\(\Rightarrow5^x\cdot\left(125+1\right)=126\)
\(\Rightarrow5^x=\dfrac{126}{126}\)
\(\Rightarrow5^x=1\)
\(\Rightarrow5^x=5^0\)
\(\Rightarrow x=0\)
b) \(\dfrac{9-3x}{2}=\dfrac{5-2x}{3}\)
\(\Rightarrow\dfrac{3\cdot\left(9-3x\right)}{6}=\dfrac{2\cdot\left(5-2x\right)}{6}\)
\(\Rightarrow3\cdot\left(9-3x\right)=2\cdot\left(5-2x\right)\)
\(\Rightarrow27-9x=10-4x\)
\(\Rightarrow-4x+9x=27-10\)
\(\Rightarrow5x=17\)
\(\Rightarrow x=\dfrac{17}{5}\)
c) \(7-4\left(x+1\right)=5\)
\(\Rightarrow4\left(x+1\right)=7-5\)
\(\Rightarrow4\left(x+1\right)=2\)
\(\Rightarrow x+1=\dfrac{1}{2}\)
\(\Rightarrow x=\dfrac{1}{2}-1\)
\(\Rightarrow x=-\dfrac{1}{2}\)