Tìm x
a , x - 1 4 = 5 3 + 1 2 b , x : 2 3 = 1 2 × 1 3
bài1. tính : a. 3 và 2/5 - 1/2 b. 4/5 + 1/5 x 3/4 c. 3 và 1/2 x 1 và 1/7 d. 4 và 1/6 : 2 và 1/3
bài2 : tính : a. 3 x 1/2 +1/4 x1/3 b. 1 và 4/5 - 2/3 : 2 và 1/3
bài 3 tìm x: a. X x 4/5 = 2 và 1/2 b. x : 3/2 = 11/4 - 5/2
sos
Bài 1
a) 3 2/5 - 1/2
= 17/5 - 1/2
= 34/10 - 5/10
= 29/10
b) 4/5 + 1/5 × 3/4
= 4/5 + 3/20
= 16/20 + 3/20
= 19/20
c) 3 1/2 × 1 1/7
= 7/2 × 8/7
= 4
d) 4 1/6 : 2 1/3
= 25/6 : 7/3
= 25/14
Bài 2
a) 3 × 1/2 + 1/4 × 1/3
= 3/2 + 1/12
= 18/12 + 1/12
= 19/12
b) 1 4/5 - 2/3 : 2 1/3
= 9/5 - 2/3 : 7/3
= 9/5 - 2/7
= 63/35 - 10/35
= 53/35
Bài 1
a) 3 2/5 - 1/2
= 17/5 - 1/2
= 34/10 - 5/10
= 29/10
b) 4/5 + 1/5 × 3/4
= 4/5 + 3/20
= 16/20 + 3/20
= 19/20
c) 3 1/2 × 1 1/7
= 7/2 × 8/7
= 4
d) 4 1/6 : 2 1/3
= 25/6 : 7/3
= 25/14
bủh
Bài 1: Tính
a) 1/3 + 1/5 - 1/4 b) 7/8 - ( 1/4 + 2/5 ) c) 5/11 - ( 3/5 - 6/11 )
Bài 2: Tìm x
a) x + 2/5 = 1/2 b) x + 3/7 = 2/5 + 3/10 c) 19/20 - x = 8/5 - 3/4
Bài 3: Tìm số tự nhiên x, biết:
a ) 4/7 < x < 1/2 + 10/3 b) 3/10 + 8/5 < x < 2/5 + 5
Giúp mình nha ^^ Ai nhanh mình Tick !!!!!!!!!❤❤
Bài 1: cho A= x^2+4x+4/x^2-4
a) tìm x để A=5/3
b) tìm x để A nguyên
Bài 2: cho x+1/x=3, tính:
a) x^2+1/x^2
b) x^5+1/x^5
a )\(A=\frac{x^2+4x+4}{x^2-4}=\frac{\left(x+2\right)^2}{x^2-2^2}=\frac{\left(x+2\right)^2}{\left(x+2\right)\left(x-2\right)}=\frac{x+2}{x-2}=\frac{5}{3}\)
<=> (x + 2).3 = (x - 2).5
<=> 3x + 6 = 5x - 10
<=> 3x - 5x = - 10 - 6
<=> - 2x = - 16
=> x = 8
b ) \(\frac{x+2}{x-2}=\frac{\left(x-2\right)+4}{x-2}=1+\frac{4}{x-2}\)
đến đây tự tìm đc
Bài 2 lớp 8 ko làm đc thì đi chết đi
Tìm X: a)X+1/4×1/5=4/5 b)3 2/3 : X=2 2/3 - 1 1/2
a)
`x+1/4xx1/5=4/5`
`x+1/20=4/5`
`x=4/5-1/20`
`x=16/20-1/20`
`x=15/20=3/4`
b)
`3 2/3:x=2 2/3-1 1/2`
`11/3:x=8/3-3/2`
`11/3:x=16/6-9/6`
`11/3:x=7/6`
`x=11/3:7/6`
`x=11/3xx6/7`
`x=22/7`
\(a,x+\dfrac{1}{4}.\dfrac{1}{5}=\dfrac{4}{5}\)
\(\Rightarrow\)\(x+\dfrac{1}{20}=\dfrac{4}{5}\)
\(\Rightarrow x=\dfrac{4}{5}-\dfrac{1}{20}=\dfrac{16}{20}-\dfrac{1}{20}=\dfrac{3}{4}\)
\(b,3\dfrac{2}{3}:x=2\dfrac{2}{3}-1\dfrac{1}{2}\)
\(\Rightarrow\dfrac{11}{3}:x=\dfrac{7}{6}\)
\(\Rightarrow x=\dfrac{11}{3}:\dfrac{7}{6}=\dfrac{22}{7}\)
Tìm x: a)x+1/4×1/5=4/5 b)3 2/3:x=2 2/3 - 1 1/2
\(a,x+\dfrac{1}{4}\times\dfrac{1}{5}=\dfrac{4}{5}\)
\(x+\dfrac{1}{20}=\dfrac{4}{5}\)
\(x=\dfrac{4}{5}-\dfrac{1}{20}\)
\(x=\dfrac{16}{20}-\dfrac{1}{20}\)
\(x=\dfrac{15}{20}=\dfrac{3}{4}\)
\(b,3\dfrac{2}{3}:x=2\dfrac{2}{3}-1\dfrac{1}{2}\)
\(\dfrac{11}{3}:x=\dfrac{8}{3}-\dfrac{3}{2}\)
\(\dfrac{11}{3}:x=\dfrac{7}{6}\)
\(x=\dfrac{11}{3}:\dfrac{7}{6}=\dfrac{22}{7}\)
a: =>x+1/20=4/5
=>x=4/5-1/20=16/20-1/20=15/20=3/4
b: =>11/3:x=8/3-3/2=16/6-9/6=7/6
=>x=11/3:7/6=11/3*6/7=66/21=22/7
Bài 1:
a, (x+1)^2-(x-1)^2-3(x+1)(x-1)
b, 5(x+2)(x-2)-1/2(6-8x)^2+17
Bài 2: Tìm x
a, 25x^2-9=0
b, (x+4)-(x+1)(x-1)=16
c, (2x-1)^2 +(x+3)^2-5(x+7)(x-7)=0
Bài 3: Tìm GTNN
A= x^2+5X=7
Bài 4 : Tìm GTLN
B= 6x -x^2-5
Bài 5:Cho x-y=-5. Tính giá trị của N=(x-y)^3-x^2+2xy-y^2
bài 1:
a) (x+1)^2-(x-1)^2-3(x+1)(x-1)
=(x+1+x-1)(x+1-x+1)-3x^2-3
=2x^2-3x^2-3
=-x^2-3
Tìm x: a) 3/4 - x =1 b) x + 4 = 1/5 c) x - 1/5 = 2 d) x + 5/3 = 1/81
a, \(x=\dfrac{3}{4}-1=\dfrac{3}{4}-\dfrac{4}{4}=-\dfrac{1}{4}\)
b, \(x=\dfrac{1}{5}-4=\dfrac{1}{5}-\dfrac{20}{5}=-\dfrac{19}{5}\)
c, \(x=2+\dfrac{1}{5}=\dfrac{10}{5}+\dfrac{1}{5}=\dfrac{11}{5}\)
d, \(x=\dfrac{1}{81}-\dfrac{5}{3}=\dfrac{1}{81}-\dfrac{135}{81}=-\dfrac{134}{81}\)
\(a,\dfrac{3}{4}-x=1\\ \Rightarrow x=1,75\\ b,x+4=\dfrac{1}{5}\\ \Rightarrow x=-3,8\\ c,x-\dfrac{1}{5}=2\\ \Rightarrow x=2,2\\ d,x+\dfrac{5}{3}=\dfrac{1}{81}\\x=\dfrac{1}{81}-\dfrac{5}{3}\\ \Rightarrow x=-\dfrac{134}{81}\)
a) \(\dfrac{3}{4}-x=1\)
\(x=\dfrac{3}{4}-1\)
\(x=-\dfrac{1}{4}\)\(=0,25\)
b) \(x+4=\dfrac{1}{5}\)
\(x=\dfrac{1}{5}-4\)
\(x=-\dfrac{19}{5}\)\(=-3,8\)
c) \(x-\dfrac{1}{5}=2\)
\(x=2+\dfrac{1}{5}\)
\(x=\dfrac{11}{5}=2,2\)
d) \(x+\dfrac{5}{3}=\dfrac{1}{81}\)
\(x=\dfrac{1}{81}-\dfrac{5}{3}\)
\(x=-\dfrac{134}{81}\)
a) \(\dfrac{1}{2}+x=\dfrac{5}{6}\)
\(\Rightarrow x=\dfrac{5}{6}-\dfrac{1}{2}=\dfrac{5}{6}-\dfrac{3}{6}=\dfrac{2}{6}=\dfrac{1}{3}\)
b) \(x+\dfrac{1}{4}=\dfrac{3}{4}\)
\(\Rightarrow x=\dfrac{3}{4}-\dfrac{1}{4}=\dfrac{2}{4}=\dfrac{1}{2}\)
c) \(x-\dfrac{1}{5}=\dfrac{3}{10}\)
\(\Rightarrow x=\dfrac{3}{10}+\dfrac{1}{5}=\dfrac{3}{10}+\dfrac{2}{10}=\dfrac{5}{10}=\dfrac{1}{2}\)
d) \(\dfrac{5}{6}-x=\dfrac{1}{3}\)
\(\Rightarrow x=\dfrac{5}{6}-\dfrac{1}{3}=\dfrac{5}{6}-\dfrac{2}{6}=\dfrac{3}{6}=\dfrac{1}{2}\)
e) \(\dfrac{3}{10}+x=\dfrac{1}{2}\)
\(\Rightarrow x=\dfrac{1}{2}-\dfrac{3}{10}=\dfrac{5}{10}-\dfrac{3}{10}=\dfrac{2}{10}=\dfrac{1}{5}\)
g) \(x+\dfrac{1}{4}=\dfrac{3}{8}\)
\(\Rightarrow x=\dfrac{3}{8}-\dfrac{1}{4}=\dfrac{3}{8}-\dfrac{2}{8}=\dfrac{1}{8}\)
a) ⇒x=56−12=56−36=26=13⇒x=56−12=56−36=26=13
b) ⇒x=34−14=24=12⇒x=34−14=24=12
c) ⇒x=310+15=310+210=510=12⇒x=310+15=310+210=510=12
d) ⇒x=56−13=56−26=36=12⇒x=56−13=56−26=36=12
e) ⇒x=12−310=510−310=210=15⇒x=12−310=510−310=210=15
g) ⇒x=38−14=38−28=18⇒x=38−14=38−28=18
Đọc tiếp
a) ⇒x=56−12=56−36=26=13⇒x=56−12=56−36=26=13
b) ⇒x=34−14=24=12⇒x=34−14=24=12
c) ⇒x=310+15=310+210=510=12⇒x=310+15=310+210=510=12
d) ⇒x=56−13=56−26=36=12⇒x=56−13=56−26=36=12
e) ⇒x=12−310=510−310=210=15⇒x=12−310=510−310=210=15
g) ⇒x=38−14=38−28=18⇒x=38−14=38−28=18
Tìm x :
a, x - 3/2 = 4/3 b, 2/5 * x = 1/3
c, x - 4/9 = 3/7 : 9/14 d, 3/5 * x - 1/2 = 1/5
a) x - 3/2 = 4/3
x = 4/3 + 3/2
x = 8/6 + 9/6 = 17/6
b) 2/5 * x = 1/3
x = 1/3 : 2/5
x = 1/3 x 5/2 = 5/6
c) x - 4/9 = 3/7 : 9/14
x - 4/9 = 2/3
x = 2/3 + 4/9
x = 6/9 + 4/9 = 10/9
d) 3/5 * x - 1/2 = 1/5
3/5 * x = 1/5 + 1/2 = 7/10
x = 7/10 : 3/5
x = 7/10 * 5/3 = 7/6
a/\(x-\dfrac{3}{2}=\dfrac{4}{3}\)
\(x=\dfrac{4}{3}+\dfrac{3}{2}\)
\(x=\dfrac{17}{6}\)
b/\(\dfrac{2}{5}\times x=\dfrac{1}{3}\)
\(x=\dfrac{1}{3}:\dfrac{2}{5}\)
\(x=\dfrac{5}{6}\)
c/\(x-\dfrac{4}{9}=\dfrac{3}{7}:\dfrac{9}{14}\)
\(x-\dfrac{4}{9}=\dfrac{2}{3}\)
\(x=\dfrac{2}{3}+\dfrac{4}{9}\)
\(x=\dfrac{10}{9}\)
d/\(\dfrac{3}{5}\times x-\dfrac{1}{2}=\dfrac{1}{5}\)
\(\dfrac{3}{5}\times x=\dfrac{1}{5}+\dfrac{1}{2}\)
\(\dfrac{3}{5}\times x=\dfrac{7}{10}\)
\(x=\dfrac{7}{10}:\dfrac{3}{5}\)
\(x=\dfrac{7}{6}\)
a,x=\(\dfrac{17}{6}\)b,x=\(\dfrac{5}{6}\)c,x=\(\dfrac{10}{9}\)d,x=\(\dfrac{7}{6}\)
Bài 1
Tìm GTLN : B=1/(x-1)^2+3
Bài 2
a) B= -8/x^2+2
b) C=1/4+2(x-2)^2
Bài 3
Tìm các giá trị x để
a)x+5/x-3<1
b)x+3/x+4>2
Bài 4
Tìm x thuộc Z để biểu thức có GTNN
a) A = 1/x-3 ; b) B = 7-x/x-5
Giúp mình nhanh đi mấy pro ơi :))