25 - (3+x)^2 = 3.(-2)^3
25 . 15 + 75 . 45
-10 . 25 - 10 . 75 + 10 . 50
3^x-2 - 2^3 = 19
(2 x - 5)^3 = - 64
2(x-1)^2 + 3 = 35
125 - 25 (x + 3) = 50
2(x+ 3) - 1x = 4
a: =25(15+45*3)
=25*150
=3750
b: \(=-10\left(25+75-50\right)=-10\cdot50=-500\)
c: =>3^x-2=27
=>x-2=3
=>x=5
d: =>2x-5=-4
=>2x=1
=>x=1/2
e: =>2(x-1)^2=32
=>(x-1)^2=16
=>x-1=4 hoặc x-1=-4
=>x=-3 hoặc x=5
f: =>25(x+3)=75
=>x+3=3
=>x=0
Cho phép tính sau: (25+7) : (56−25)× ( 8 : 3) :2+64 ×3%
Phép tính nào thực hiện được trong chương trình bảng tính?
A.
=(25+7)/(56-25)x(8/3)/2+6^4x3%
B.
=(25+7)/(56-2^5)x(8/3):2+6^4x3%
C.
=(25+7)/(56-25)*(8/3)/2+64* 3%
D.
=(25+7)/(56-2/5)x(8/3)/2+6^4x3%
1/ (\(\left(-\dfrac{2}{3}\right)\)\(^2\) x \(\dfrac{-9}{8}\) - 25% x \(\dfrac{-16}{5}\)
2/ -1\(\dfrac{2}{5}\) x 75% + \(\dfrac{-7}{5}\) x 25%
3/ -2\(\dfrac{3}{7}\) x (-125%) + \(\dfrac{-17}{7}\) x 25%
4/ (-2)\(^3\) x (\(\dfrac{3}{4}\) x 0.25) : (2\(\dfrac{1}{4}\) - 1\(\dfrac{1}{6}\))
1) Ta có: \(\left(-\dfrac{2}{3}\right)^2\cdot\dfrac{-9}{8}-25\%\cdot\dfrac{-16}{5}\)
\(=\dfrac{4}{9}\cdot\dfrac{-9}{8}-\dfrac{1}{4}\cdot\dfrac{-16}{5}\)
\(=\dfrac{-1}{2}+\dfrac{4}{5}\)
\(=\dfrac{-5}{10}+\dfrac{8}{10}=\dfrac{3}{10}\)
2) Ta có: \(-1\dfrac{2}{5}\cdot75\%+\dfrac{-7}{5}\cdot25\%\)
\(=\dfrac{-7}{5}\cdot\dfrac{3}{4}+\dfrac{-7}{5}\cdot\dfrac{1}{4}\)
\(=\dfrac{-7}{5}\left(\dfrac{3}{4}+\dfrac{1}{4}\right)=-\dfrac{7}{5}\)
3) Ta có: \(-2\dfrac{3}{7}\cdot\left(-125\%\right)+\dfrac{-17}{7}\cdot25\%\)
\(=\dfrac{-17}{7}\cdot\dfrac{-5}{4}+\dfrac{-17}{7}\cdot\dfrac{1}{4}\)
\(=\dfrac{-17}{7}\cdot\left(\dfrac{-5}{4}+\dfrac{1}{4}\right)\)
\(=\dfrac{17}{7}\)
4) Ta có: \(\left(-2\right)^3\cdot\left(\dfrac{3}{4}\cdot0.25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(=\left(-8\right)\cdot\left(\dfrac{3}{4}\cdot\dfrac{1}{4}\right):\left(\dfrac{9}{4}-\dfrac{7}{6}\right)\)
\(=\left(-8\right)\cdot\dfrac{3}{16}:\dfrac{54-28}{24}\)
\(=\dfrac{-3}{2}\cdot\dfrac{24}{26}\)
\(=\dfrac{-72}{52}=\dfrac{-18}{13}\)
bài 2 viết mỗi tích, thương sau dưới dạng luỹ thừa
a) 4^10 x 2^30 b) 9^25 x 27^4 x 81^3 c) 25^50 x 125^5 d) 64^3 x 4^8 x 16^4
e)3^8:3^6 ; 2^10:8^3 ; 12^7 :6^7 ; 31^5 ; 81^3
f) 5^8 : 25^2 ; 4^9:64^2 ; 2^25 : 32^4 ; 125^3 : 25^4
a, 410. 230=220.230=250
b,925.274.813= 350.312.312=374
Tương tự các câu khác....
a, 410.230 = (22)10.230 = 220.230 = 250
b, 925.274.813 = (32)25.(33)4.(34)3 = 350.312.312 = 374
c, 2550.1255 = (52)50.(53)5 = 5100.515 = 5115
d, 643.48.164 = (26)3.(22)8.(24)4 = 218.216.216 = 250
e, 38 : 36 = 32
210 : 83 = 210 : (23)3 = 210 : 29 = 2
127 : 67 = (12 : 6)7 = 27
@Dương Tuyết Mai
11×(x-9)+22=99
4×(x-3)+1=49
25+3×(x-8)=106
9×(x-4)-25=20
5+20÷(x+3)=7
25-14÷(2×X-3)=23
5+4×(2×X-3)=25
40-21÷(2×X+3)=33
1. 11(x-9)=77
x-9=7
x=16
2. 4(x-3)=48
x-3=12
x=15
3.3(x-8)=81
(x-8)=27
x=35
\(40-21:\left(2.x+3\right)=33\)
\(21:\left(2.x+3\right)=40-33\)
\(21:\left(2.x+3\right)=7\)
\(\left(2.x+3\right)=21:7\)
\(\left(2.x+3\right)=3\)
\(2.x=3-3\)
\(2.x=0\)
\(x=0:2\)
\(x=0\)
4 x 25 - 12 x 5 + 170 : 10
( 7 + 3 mũ 3 : 3 mũ 2 ) x 4 - 3
12 : {400 :[ 500 - ( 125 + 25 x 7 )]}
168 + { [ 2 x (2 mũ 4 + 3 mũ 2 ) - 256 mũ 0 ] : 7 mũ 2
a) 4.25-12.5+170:10
=100-60+17
=40+17
=57
b) (7+33:32).4-3
=(7+3).4-3
=10.4-3
=40-3
=37
c) 12:{400:[500-(125+25.7)]}
=12:{400:[500-(125+175)]}
=12:{400:[500-300]}
=12:{400:200}
=12:2
=6
d) 168+{[2.(24+32)-2560]:72}
=168+{[2.(16+9)-1]:49}
=168+{[2.25-1]:49}
=168+{[50-1]:49}
=168+{49:49}
=168+1
=169
25 x 2 + 25 x 3 - 3 x 25
\(=25\times\left(2+3-3\right)\)
\(=25\times2\)
\(=50\)
\(25\left(2+3-3\right)\)
\(=25\cdot2\)
\(=50\)
25 x 2+ 25 x 3 - 3 x 25
= 25 x ( 2 + 3 - 3 )
= 25 x 2
= 50
Tính thuận tiện nhất :
*Lưu ý : Trình bài đầy đủ *
1) 2/5 x 3/4 + 3/4 x 3/5
2) 41/25 x 1/2 - 16/25 x 1/2
3) 4/5 : 3/5 - 2/3 : 3/5
1)
2/5x3/4+3/4x3/5
= 3/10+9/20
=6/20+9/20
=3/4
1)
2/5x3/4+3/4x3/5
= 3/10+9/20
=6/20+9/20
2)
= 41/50-8/25
=41/50-16/50
=1/2
3)
=4/3-10/9
=12/9-10/9
=2/9
=3/4
ngan:3
1, Thực hiện phép tính :
a,2^3 - 2^3 - 2^2 -( -2 )^2 +4^2 . (- 4) ^2
b, ( - 6 ) ^ 2 . (-2 )^ 3 +(-4 )^3 .(-4 )^2 +(-1 )^25 + (-1 )^26
c, 4^2 . (-25 )^ 4 :2^4 . 25 ^3
d, -2 ^3 .(-2)^4 : 2^6
2, tìm x thuộc Z biết :
a, x^2 -(-3 )^2 =16
b, x^2 + (-4) ^2 =0
c, ( x - 3 ). (x^2 -4 ) =0
(2^3-2^3)-(2^2-(-2)^2+(4^2*(-4)^2)=0-0+256=256
2, tìm x thuộc Z biết :
a, x^2 -(-3 )^2 =16
x^2-9 = 16
x^2 = 25
=> x = 5
b, x^2 + (-4) ^2 =0
x^2 + 16 = 0
x^2 = -16
=> x= -4
(12/25)^x=(5/3)^-2-(-3/5)^4
(12/25)^x=144/625
(12/25)^x=(12/25)^2
=>x=2