Ét o ét . giúp tui, cần gấp
a) 4/15 x 2016/2018+ 4/15 x 3/2018- 4/15 x 1/2018 b) 8/15 x 8 - 2 x 8/15+3 x 8/15+ 8/15
tính bằng cách thuận tiện
a) 4/15 x 2016/2018+ 4/15 x 3/2018- 4/15 x 1/2018 b) 8/15 x 8 - 2 x 8/15+3 x 8/15+ 8/15a) 4/15 x 2016/2018+ 4/15 x 3/2018- 4/15 x 1/2018
= 4/15 x (2016/2018 + 3/2018 - 1/2018)
= 4/15 x (\(1\frac{1}{2018}\)-1/2018)
=4/15 x 1
= 4/15
b) 8/15 x 8 - 2 x 8/15+3 x 8/15+ 8/15
= 8/15 x ( 8 - 2 + 3 + 1)
= 8/15 x 10
= 80/15 => \(5\frac{1}{3}\)
Mấy cái kia mình lười làm phân số nên mình chỉ viết rõ hỗn số thôi, bạn thông cảm nha. Chúc bạn học giỏi <3
giúp mình nốt câu này nhaa :(
Tìm số tự nhiên x sao cho:
a) 208 − 8. ( x + 4 ) = 2 3 .5
b) 15 + 5. ( x − 2018 ) = 3.2 2 .5
c) 2018. ( 2019 − x ) = 0
a)
208 − 8. ( x + 4 ) = 2 3 .5 8. ( x + 4 ) = 208 − 40 = 168 x = 17
b)
208 − 8. ( x + 4 ) = 2 3 .5 8. ( x + 4 ) = 208 − 40 = 168 x = 17
c)
2018. ( 2019 − x ) = 0 x = 2019
1,Tính giá trị biểu thức
a, 13 . 17 - 256 : 16 + 14 : 7 - 1
b, 15 . 24 - 14 . 5 . (145 : 5 - 27)
c, 15 . 8 - (17 - 30 + 83) - 144 : 6
d,18 - 4 . (27 - 90 + 73) : 10
2,Tìm x
a, 315 - (135 - x)=215
b, x - 320 : 32 = 25 . 16
c, 3 . x - 2018 : 2 = 23
d, 280 - 9 . x - x = 80
e, 38 . x - 12 . x - x . 16 = 40
Giúp mình với nhé,mình đang cần gấp !!
2,
a) \(315-\left(135-x\right)=215\)
\(\Rightarrow135-x=315-215\)
\(\Rightarrow135-x=100\)
\(\Rightarrow x=135-100\)
\(\Rightarrow x=35\)
b) \(x-320:32=25\cdot16\)
\(\Rightarrow x-10=5^2\cdot4^2\)
\(\Rightarrow x-10=20^2\)
\(\Rightarrow x-10=400\)
\(\Rightarrow x=410\)
c) \(3\cdot x-2018:2=23\)
\(=3\cdot x-1009=23\)
\(\Rightarrow3\cdot x=1032\)
\(\Rightarrow x=1032:3\)
\(\Rightarrow x=344\)
d) \(280-9\cdot x-x=80\)
\(\Rightarrow280-x\cdot\left(9+1\right)=80\)
\(\Rightarrow280-10\cdot x=80\)
\(\Rightarrow10\cdot x=280-80\)
\(\Rightarrow10\cdot x=200\)
\(\Rightarrow x=20\)
e) \(38\cdot x-12\cdot x-x\cdot16=40\)
\(\Rightarrow x\cdot\left(38-12-16\right)=40\)
\(\Rightarrow x\cdot10=40\)
\(\Rightarrow x=40:10\)
\(\Rightarrow x=4\)
giải các phương trình:
\(\dfrac{1}{x+1}-\dfrac{5}{x-2}=\dfrac{15}{\left(x+1\right)\left(x-2\right)}\)
\(\dfrac{x-1}{x+2}-\dfrac{x}{x-2}=\dfrac{5x-2}{4-x^2}\)
\(\dfrac{x+2}{2020}+\dfrac{x+4}{2018}=\dfrac{x+6}{2016}+\dfrac{x+8}{2014}\)
Giúp tớ với, thầy réo tớ kinh lắm rồi!
\(\dfrac{1}{x+1}\)-\(\dfrac{5}{x-2}\)=\(\dfrac{15}{\left(x+1\right)\left(x-2\right)}\)
\(\Leftrightarrow\)\(\dfrac{x-2}{\left(x+1\right)\left(x-2\right)}\)-\(\dfrac{5\left(x+1\right)}{\left(x+1\right)\left(x-2\right)}\)=\(\dfrac{15}{\left(x+1\right)\left(x-2\right)}\)
\(\Leftrightarrow\)x-2-5(x+1)=15
\(\Leftrightarrow\) x-2-5x-5=15
\(\Leftrightarrow\)x-5x=15+2+5
\(\Leftrightarrow\)-4x=22
\(\Leftrightarrow\)x=-\(\dfrac{11}{2}\)
vậy
a)\(\frac{x+1}{5}+\frac{x+1}{6}+\frac{x+1}{7}=\frac{x+1}{8}+\frac{x+1}{9}\)
b)\(\frac{x+6}{2015}+\frac{x+5}{2016}+\frac{x+4}{2017}=\frac{x+3}{2018}+\frac{x+2}{2019}+\frac{x+1}{2010}\)
c)\(\frac{x+6}{2016}+\frac{x+7}{2017}+\frac{x+8}{2018}=\frac{x+9}{2019}+\frac{x+10}{2020}+1\)
d)\(\frac{x-90}{10}+\frac{x-76}{12}+\frac{x-58}{14}+\frac{x-36}{16}+\frac{x-15}{17}=15\)
ai xong nhanh nhất và đúng em xin gửi 2 SP ạ
a) \(\frac{x+1}{5}+\frac{x+1}{6}+\frac{x+1}{7}=\frac{x+1}{8}+\frac{x+1}{9}\)
\(\Leftrightarrow\frac{x+1}{5}+\frac{x+1}{6}+\frac{x+1}{7}-\frac{x+1}{8}-\frac{x+1}{9}=0\)
\(\Leftrightarrow\left(x+1\right).\left(\frac{1}{5}+\frac{1}{6}+\frac{1}{7}-\frac{1}{8}-\frac{1}{9}\right)=0\)
\(\Leftrightarrow x+1=0\)
\(\Leftrightarrow x=0-1\)
\(\Rightarrow x=-1\)
Vậy \(x=-1.\)
Mình chỉ làm câu a) thôi nhé.
Chúc bạn học tốt!
Lê Thị Thục HiềnTrần Thanh PhươngVũ Minh Tuấn?Amanda?Nguyễn Việt LâmHISINOMA KINIMADONguyễn Huy TúAkai Haruma
8/15 + 4/15 :2/5= ét ô ét
8/15 + 4/15 :2/5 = 8/15 + 2/5 = 14/15
TÍNH NHANH
a) 3/16 + 4/15 + 5/16 + 1/15
b) 6/7 x 8/15 x 7/6 x 15/16
c) 19/20 x 13/21 + 9/20 x 8/21
d) (1+ 10/15 ) x (1+ 1/16 ) x ( 1+ 1/17 ) x ( 1+ 1/18 )
MINK ĐANG CẦN GẤP
a) \(\frac{3}{16}+\frac{4}{15}+\frac{5}{16}+\frac{1}{15}\)
\(=\left(\frac{3}{16}+\frac{5}{16}\right)+\left(\frac{4}{15}+\frac{1}{15}\right)\)
\(=\frac{1}{2}+\frac{1}{3}\)
\(=\frac{5}{6}\)
b) \(\frac{6}{7}\times\frac{8}{15}\times\frac{7}{6}\times\frac{15}{16}\)
\(=\left(\frac{6}{7}\times\frac{7}{6}\right)\times\left(\frac{8}{15}\times\frac{15}{16}\right)\)
\(=1\times\frac{1}{2}=\frac{1}{2}\)
c) \(\frac{19}{20}\times\frac{13}{21}+\frac{9}{20}\times\frac{8}{21}\)
\(=\frac{19\times13}{20\times21}+\frac{9\times8}{20\times21}\)
\(=\frac{247}{420}+\frac{72}{420}\)
\(=\frac{319}{420}\)
tích cho chị nha
câu a) = 5/6
câu b = 1/2
câu c = 319/420
Bài 2.Tìm x
a,(x-2018) .3=0
b,25(x-8)=0
c,25+(15+x)=75
a) \(\left(x-2018\right)\cdot3=0\)
\(\Leftrightarrow x-2018=0\)
\(\Leftrightarrow x=2018\)
b) \(25\left(x-8\right)=0\)
\(\Leftrightarrow x-8=0\)
\(\Leftrightarrow x=8\)
c) \(25+\left(15+x\right)=75\)
\(\Leftrightarrow15+x=50\)
\(\Leftrightarrow x=35\)
a) x=2018
b)x=8
c)x=35
Bài 2:
a, (x-2018).3=0
<=> x-2018=0
<=>x=0+2018
<=>x=2018
Vậy x=2018
b, 25(x-8)=0
<=> x-8=0
<=> x=0+8
<=>x=8
Vậy x=8
c, 25+(15+x)=75
<=> 25+15+x=75
<=> 40+x=75
<=>x=75-40
<=>x=35
Vậy x=35
Bài 4 : Tính nhanh :
a, 15 x 64 + 25 x 100 + 36 x 15 + 60 x 100
b, 47^2 + 48^2 -25 + 94 x 48
c, 9^3 - 9^2 x ( -1) - 9 x 11 + ( -1) x 11
d,2016 x 2018 - 2017^2
Giúp mk vs ạ mk đang cần gấp
Bài 4 : Tính nhanh :
a, 15. 64 + 25. 100 + 36. 15 + 60. 100
= (15 . 64 + 36. 15) + (25. 100 + 60. 100)
= 15.(64 + 36) + 100.(25 + 60)
= 15. 100 + 100. 85
= 100.(15 + 85)
= 100. 100
= 10000
b, 472 + 482 - 25 + 94. 48
= 472 + 2.47. 48 + 482 - 25
= (47 + 48)2 - 52
= (47 + 48 - 5)(47 + 48 + 5)
= (48 + 22)(48 + 52)
= 90. 100
= 9000
c, 93 - 92. ( -1) - 9. 11 + ( -1). 11
= 93 + 92 + 11(- 9 - 1)
= 92.(9 + 1) + 11. (-10)
= 81. 10 - 110
= 810 - 110
= 700
d,2016. 2018 - 20172
= (2017 - 1)(2017 + 1) - 20172
= 20172 - 1 - 20172
= -1
#Học tốt!