Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
1 (3y - 0,8 ) : y + 14,5 = 15
( 3y - 0,8 ) : y = 0,5
3y : y - 0,8 : y = 0,5
3 - 0,8 : y = 0,5
0,8 : y = 2,5
y = 0,8 : 2,5
y = 0,32
Ta có :
Tử số = 2012 x 14 + 1997 + 2010 x 2011
= ( 2011 + 1 ) x 14 + 1997 + 2010 x 2011
= 2011 x 14 + 1 x 14 + 1997 + 2010 x 2011
= 2011 x 14 + 14 + 1997 + 2010 x 2011
= ( 2011 x 14 ) + ( 14 + 1997 ) + ( 2010 x 2011 )
= 2011 x 14 + 2011 + 2010 x 2011
= 2011 x ( 14 + 1 + 2010 )
= 2011 x 2025
Mẫu số = 2011 x 5 + 2011 x 1008 + 1012 x 2011
= 2011 x ( 5 + 1008 + 1012 )
= 2011 x 2025
=> \(A=\frac{2011\times2025}{2011\times2025}=1\)
\(a,12,3\cdot4,7+5,3\cdot12,3-1,4\cdot7,5+7,5\cdot5,4\)
\(=12,3\cdot\left(4,7+5,3\right)-7,5\cdot\left(1,4+5,4\right)\)
\(=12,3\cdot10-7,5\cdot6,8\)
\(=123-51\)
\(=72.\)
\(b,3\cdot x-1=\frac{3}{4}:\frac{15}{16}\)
\(\Leftrightarrow3\cdot x-1=\frac{3}{4}\cdot\frac{16}{15}\)
\(\Leftrightarrow3\cdot x-1=\frac{4}{5}\)
\(\Leftrightarrow3\cdot x=\frac{4}{5}+1\)
\(\Leftrightarrow3\cdot x=\frac{9}{5}\)
\(\Leftrightarrow x=\frac{9}{5}\div3\)
\(\Leftrightarrow x=\frac{9}{5}\cdot\frac{1}{3}\)
\(\Leftrightarrow x=\frac{3}{5}\)
a) \(12,3\times4,7+5,3\times12,3-1,4\times7,5+7,5\times5,4\)
\(=12,3\times\left(4,7+5,3\right)+7,5\times\left(5,4-1,4\right)\)
\(=12,3\times10+7,5\times4\)
\(=123+30\)
\(=153\)
b) \(3.x-1=\frac{3}{4}:\frac{15}{16}\)
\(\Rightarrow3.x-1=\frac{4}{5}\)
\(\Rightarrow3.x=\frac{9}{5}\Rightarrow x=\frac{3}{5}\)
\(11\left(x-6\right)=4x+11\)
\(\Rightarrow11x-66=4x+11\)
\(\Rightarrow11x-4x=66+11\)
\(\Rightarrow7x=77\)
\(\Rightarrow x=11\)
Vậy x = 11
\(\left(3x+0,8\right)\div x+14,5=15\)
\(\Rightarrow\left(3x+0,8\right)\div x=15-14,5\)
\(\Rightarrow\left(3x+0,8\right)\div x=0,5\)
\(\Rightarrow3x+0,8=0,5x\)
\(\Rightarrow-2,5x=0,8\)
\(\Rightarrow x=0,8\div\left(-2,5\right)=\frac{-8}{25}\)
Vậy x = \(\frac{-8}{25}\)
\(1,2\cdot35+2,56:0,8+58\\ =42+3,2+58\\ =103,2\\ \\ \left(23+15:2,5\right):14,5+17\\ =\left(23+6\right):14,5+17\\ =29:14,5+17=2+17\\ =19\)
Bài 1
a) -(515-80+91)-(2003+80-91)= -515+80-91-2003-80+91=(80-80)+(-91+91)+(-515-2003)=0+0+(-2518)= -2518
b)-(-85)-(-71)+15+(-85)=85+71+15+-85=(85-85)+(71+15)=0+86=86
c)-(537-812)+(-163-712)-(-364)= -537+812+-163-712+364=(812-712)+(-537-136)+364=0+(-700)+364= -236
Bài 2
a)25-(x+4)= -19+3 c) I2x-5l=13
25-(x+4)= -16 suy ra 2x-5 thuộc {13;-13}
(x+4)= 25-(-16) TH1: 2x-5=13 vậy x=9
x+4 =41 TH2: 2x-5= -13 vậy x= -4
x =41-4
x =37
a: \(\Leftrightarrow x\cdot12.3=123\)
=>x=10
b: \(\dfrac{3x-0.8}{x}+14.5=15\)
\(\Leftrightarrow\dfrac{3x-0.8}{x}=0.5\)
\(\Leftrightarrow3x-0.8=0.5x\)
=>2,5x=0,8
hay x=8/25
c: \(\Leftrightarrow12.5\cdot x=5.58-4.85=0.73\)
hay x=73/1250