a: \(\dfrac{1}{2}B=\dfrac{1}{2^2}+\dfrac{1}{2^3}+...+\dfrac{1}{2^{100}}\)
\(\Leftrightarrow-\dfrac{1}{2}B=\dfrac{1}{2^{100}}-\dfrac{1}{2}\)
hay \(B=\dfrac{-1}{2^{99}}+1\)
b: |3x+5|=10
=>3x+5=10 hoặc 3x+5=-10
=>3x=5 hoặc 3x=-15
=>x=-5 hoặc x=5/3
1)Tìm x biết: \(\dfrac{1}{2}-\left(\dfrac{1}{3}-\left(\dfrac{1}{4}-\left(\dfrac{1}{5}-x\right)\right)\right)=1\)
2) Tính B = \(\dfrac{2.5^{22}-9.5^{21}}{25^{10}}:\dfrac{5\left(3.7^{15}-19.7^{14}\right)}{7^{16}+3.7^{15}}\)
a)\(\frac{-3}{2}-2x+\frac{3}{4}=-2\)
b)\(\left(\frac{-2}{3}x-\frac{3}{5}\right)\left(\frac{3}{-2}-\frac{10}{3}\right)=\frac{2}{5}\)
c)\(\frac{x}{2}-\left(\frac{3x}{5}-\frac{13}{5}\right)=-\left(\frac{7}{5}+\frac{7}{10}.x\right)\)
d)\(\frac{2x-3}{3}+\frac{-3}{2}=\frac{5-3x}{6}-\frac{1}{3}\)
e)\(\frac{2}{3x}-\frac{3}{12}=\frac{4}{5}-\left(\frac{7}{x}2\right)\)
k)\(\frac{13}{x-1}+\frac{5}{2x-2}-\frac{6}{3x-3}\)
m)\(\left(\frac{3}{2}-\frac{2}{-5}\right):x-\frac{1}{2}=\frac{3}{2}\)
n)\(\left(\frac{3}{2}-\frac{5}{11}-\frac{3}{13}\right)\left(2x-2\right)=\left(\frac{-3}{4}+\frac{5}{22}+\frac{3}{26}\right)\)
Giải giúp mk
mk đang cần ghấp trong hôm nay
cám ơn mọi người
Tìm x biết : a) x+3/22=-27/121.11/9 b) (3và2/20-2và1/20)x+2/7=3/5 c) |3/2x-5|-1/2=-1/4
Thu gọn các đơn thức đồng dạng trong đa thức sau:
a) \(A=x^5-\dfrac{1}{2}x+7x^3-2x+\dfrac{1}{5}x^3+3x^4-x^5+\dfrac{2}{5}x^4+15\)
b) \(B=3x^2-10+\dfrac{2}{5}x^3+7x-x^2+8+7x^2\)
c) \(C=\dfrac{1}{7}x-2x^4+5x+6\)
1)Tính giá trị biểu thức:
\(\dfrac{\left(13\dfrac{1}{4}-2\dfrac{5}{27}-10\dfrac{5}{6}\right).230\dfrac{1}{25}+46\dfrac{3}{4}}{\left(1\dfrac{3}{7}+\dfrac{10}{3}\right):\left(12\dfrac{1}{3}-14\dfrac{2}{7}\right)}\)
2)Tìm x biết:
a) \(42+\dfrac{3}{7}.\left|3x-1\right|=12\)
b) \(\left|2x-1\right|=\left|x+2\right|\)
c) \(2.3^x.3^2=18\) với \(x\in N\)
Tìm x biết :
1) \(\dfrac{-7}{x+1}=\dfrac{-x-1}{\dfrac{4}{7}}\)
2) \(\dfrac{x-3}{x+5}=\dfrac{5}{7}\)
3) \(\dfrac{x+1}{2x+1}=\dfrac{0,5x+2}{x+3}\)
4) \(\dfrac{3x+2}{5x+7}=\dfrac{3x-1}{5x+1}\)
1.Tìm x biết: |3 - x| + 3x - 1 = 0
2. Tìm x thỏa mãn \(\dfrac{x-10}{30}+\dfrac{x-14}{43}+\dfrac{x-5}{95}+\dfrac{x-148}{8}=0\)
Tìm x,y,z,t biết
a,x:y:z:t=15:7:3:1 và x-y+z-t=10
b,\(\frac{x}{5}=\frac{y}{6},\frac{y}{8}=\frac{z}{7}vàx+y-z=69\)
c,2x=3y,5y=7z và 3x+5z-7y
d,\(\frac{x-1}{2}=\frac{y+3}{4}=\frac{z-5}{6}và5z-3x-4y=50\)
Giúp vs ạ, cần trước 5 h chiều
I) Tìm x biết:
1)
a, l \(\frac{1}{2}x\)l =3 - 2x
b, lx-1l = 3x + 2
c) l 5xl =x - 12
d) l 17-x l =5x+1
2)
a, l 9+x l =2x
b) l 5xl -3x =2
c) lx+6l - 9 =2x
d, l 2x-3 l +x =21
3,
a, l 4+2x l = -4x
b, l3x-1l + 2 = x
c) l x+15l +1 = 3x
d, l 2x-5 l +x = 2
4,
a, l 2x - 5 l = x+1
b, l 3x -2 l -1 + x
c) l 3x -7l = 2x +1
d, l2x -1l +1 = x
