3/8 x X+1/4xX=2/5
Tìm X:
a,2xX-5=21
b,3/4+1/4xX=5/6
c,7/8-1/2xX=5/6
d(1/1x2+1/2x3+1/3x4)x100-[5/2:(X+206/100)]:1/2=89
\(a)\) \(2x-5=21\)
\(\Leftrightarrow\) \(2x=21+5\)
\(\Leftrightarrow\) \(2x=26\)
\(\Leftrightarrow\) \(x=26:2\)
\(\Leftrightarrow\) \(=13\)
\(b)\) \(\frac{3}{4}+\frac{1}{4}x=\frac{5}{6}\)
\(\Leftrightarrow\) \(\frac{1}{4}x=\frac{5}{6}-\frac{3}{4}\)
\(\Leftrightarrow\) \(\frac{1}{4}x=\frac{1}{12}\)
\(\Leftrightarrow\) \(x=\frac{1}{3}\)
\(c)\) \(\frac{7}{8}-\frac{1}{2}x=\frac{5}{6}\)
\(\Leftrightarrow\) \(\frac{1}{2}x=\frac{7}{8}-\frac{5}{6}\)
\(\Leftrightarrow\) \(\frac{1}{2}x=\frac{1}{24}\)
\(\Leftrightarrow\) \(x=\frac{1}{12}\)
1. Tìm X bt
a,(4'1/2-2x)x 3'2/3=11/5
4'1/2 là bốn một phần hai
b.3/4xX+4/7xX=-15/8
4'1/2 là bốn ,một phần hai
giúp mik vs
a) \(\left(4\frac{1}{2}-2x\right)\cdot3\frac{2}{3}=\frac{11}{5}\)
\(\left(\frac{9}{2}-2x\right)=\frac{11}{5}\cdot\frac{3}{11}\)
\(2x=\frac{45-6}{10}\)
\(2x=\frac{39}{10}\)
\(x=\frac{39}{10\cdot2}=\frac{39}{20}\)
b) \(\frac{3}{4}\cdot x+\frac{4}{7}\cdot x=-\frac{15}{8}\)
\(x\cdot\left(\frac{21+16}{28}\right)=-\frac{15}{8}\)
\(x=-\frac{15}{8}\cdot\frac{28}{37}\)
\(x=-\frac{105}{74}\)
Tìm x
1/4xX-(x-4/5)-1/2=2x-6
1/4 . x - (x - 4/5) - 1/2 = 2x - 6
1/4 x - x + 4/5 - 1/2 = 2x - 6
1/4 x - x - 2x = -6 - 4/5 + 1/2
-11/4 x = -63/10
x = -63/10 : (-11/4)
x = 126/55
BÀi 7 tìm số tự nhiên x biết
d) 35 : ( 2x x + 3) - 3 = 11 - 9 x 2,5 x 0,4; 8xx+ 4xx- 44=100; 5xx+ 3xx+ 4 = 68
e) ( x+1) + ( x+2) ....... + ( x + 211) = 23632
f) (1+3+5+7+........+2009) + x = 1010026
bài 8: tính hợp lí
( 98x 7676 - 9898 x 76) : ( 2+4 +6+........+200)
e) (x + 1) + (x + 2) + .... + (x + 211) = 23632
(x + x + .... + x) + (1 + 2 + ... + 211) = 23632
211x + 22366 = 23632
211x = 23632 - 22366
211x = 1266
=> x= 6
f) (1 + 3 + 5 + 7 + .... + 2009) + x = 1010026
Số số hạng của 1 + 3 + 5 + 7 + .... + 2009 là: (2009 - 1) : 2 + 1 = 1005
Tổng của 1 + 3 + 5 +... + 2009 là: (1 + 2009) x 1005 : 2 = 1010025
Ta được : 1010025 + x = 1010026
=> x = 1010026 - 1010025 = 1
Bài 8:
( 752248-752248) : ( 2+4+6+...+200)
0 : ( 2+4+6+200)=0
Chúc bạn hok tốt nha!
2:Tính:
a.4/3+5/6 b.6/5-4/9 c.5/4x4 d.2/5:3/5
1.
2/3+x=7/6
3/4xX=9/2
a) \(\dfrac{13}{6}\)b) \(\dfrac{7}{18}\)c) \(5\) d) \(\dfrac{2}{3}\)
1.
a)x\(=\)\(\dfrac{7}{6}\)\(-\dfrac{2}{3}\)
x\(=\dfrac{1}{2}\)
b)x\(=\dfrac{9}{2}:\dfrac{3}{4}\)
x\(=6\)
LỘN LỚP GÙI CÁI ĐẤY KIẾN THỨC LỚP 4 MÀ CỤ
(1/4xX-1/8)x3/4=1/4
Tim x
(1/4x X -1/8 ) x 3/4 =1/4 1/4 x X -1/8 = 1/4 : 3/4 ( tìm thừa số ) 1/4 x X - 1/8 = 1/3 1/4 x X = 1/3 + 1/8 ( tìm số hạng ) 1/4 x X = 11/24 X = 11/24 : 1/4 ( tìm thừa số ) X = 11/6
( 5xX+7):2= 16 128 - 3 x(X - 4)=23 [ (4xX+28) x 3+55 ] :5=35
\(\left(5\cdot x+7\right):2=16\) \(128-3\cdot\left(x-4\right)=23\)
\(\left(5\cdot x+7\right)=16\cdot2\) \(3\cdot\left(x-4\right)=128-23\) \([\left(4\cdot x+28\right)\cdot3+55]:5=35\)
\(\left(5\cdot x+7\right)=32\) \(3\cdot\left(x-4\right)=105\) \([\left(4\cdot x+28\right)\cdot3+55]=35\cdot5\)
\(5\cdot x=32-7\) \(x-4=105:3\) \([\left(4\cdot x+28\right)\cdot3+55]=175\)
\(5\cdot x=25\) \(x-4=35\) \(\left(4\cdot x+28\right)\cdot3=175-55\)
\(x=25:5\) \(x=35+4\) \(\left(4\cdot x+28\right)\cdot3=120\)
\(x=5\) \(x=39\) \(\left(4\cdot x+28\right)=120:3\)
\((4\cdot x+28)=40\)
\(4\cdot x=40-28\)
\(4\cdot x=12\)
\(x=12:4\)
\(x=3\)
Chúc bạn hok tốt !
a) 5x X+7=16x2 b)3x(X-4)=128-23 c)(4x X +28 ) x 3 + 55 = 35 x 5
5xX+7=32 3x(X-4)=105 (4x X + 28) x3 +55 =175
5xX=32-7 X-4 = 105 : 3 (4x X + 28 ) x3 = 175 -55
5xX=25 X-4 = 35 (4x X + 28 ) x3 = 120
X=25:5 X = 35 + 4 4x X + 28 = 120 : 3=40
X=5 X = 39 X = (40-28):4=3
75%xX+3/4xX+X=30
x+0,25= 18/5+43/4
1.
a, (2x-3) x (y+5)= 3
b, Xxy- - 3xX + 2xy=13
c, Xxy - 4xX - 3xy = 5