2/3 + 1/3 : x = 1/2
giúp mình với
a, x-1/4=5/3
b, x:2/3=1/2
giúp mình với ạ!!
Tìm x:
a,50%x - 0,2 + x =4/5
b,(x - 3/4) : 1/2 + 3/2 =25/2
Giúp mình với!! mình cần gấp!! Cảm ơn
\(a,50\%x-0,2+x=\dfrac{4}{5}\)
\(\Leftrightarrow\dfrac{1}{2}x-0,2+x=\dfrac{4}{5}\)
\(\Leftrightarrow\dfrac{1}{2}x+x=\dfrac{4}{5}+0,2\)
\(\Leftrightarrow\dfrac{3}{2}x=\dfrac{4}{5}+\dfrac{1}{5}\)
\(\Leftrightarrow\dfrac{3}{2}x=1\)
\(\Leftrightarrow x=\dfrac{2}{3}\)
\(b,\left(x-\dfrac{3}{4}\right):\dfrac{1}{2}+\dfrac{3}{2}=\dfrac{25}{2}\)
\(\Leftrightarrow\left(x-\dfrac{3}{4}\right).2=\dfrac{25}{2}-\dfrac{3}{2}\)
\(\Leftrightarrow\left(x-\dfrac{3}{4}\right).2=\dfrac{22}{2}\)
\(\Leftrightarrow x-\dfrac{3}{4}=11:2\)
\(\Leftrightarrow x=\dfrac{11}{2}+\dfrac{3}{4}\)
\(\Leftrightarrow x=\dfrac{25}{4}\)
Tìm x
(4x+3)2+(3x-4)2+(2+5x)(2-5x)=x
Thu gọn biểu thức
a)(x-3)(x+3)-(x-3)2
b)(3x-1)2+2(3x-1)(2x+1)+(2x+1)2
giúp mình với ;-;
1) \(\Rightarrow16x^2+24x+9+9x^2-24x+16+4-25x^2=x\)
\(\Rightarrow x=29\)
2)
a) \(=x^2-9-x^2+6x-9=6x-18\)
b) \(=\left(3x-1+2x+1\right)^2=\left(5x\right)^2=25x^2\)
triển khai các tích sau
a)( 1/2m+3)3
b)[2(m+1/2)]
c)(2 căn x+1)2 vớix>0
d)(+1/4)2
giúp mình với mình cần gấp
c) \(\left(2\sqrt{x}+1\right)^2=4x+4\sqrt{x}+1\)
Bài 9: Tìm x, biết:
a)|-2x+1,5|=1/4
b)3/2-|1 1/4+3x|=1/4
c)|4x-1| - |3x-1/2|=0
d)|x-1|-2x=1/2
Giúp mình với mình đang cần gấp
\(|-2x+1,5|=\dfrac{1}{4}\Rightarrow-2x+1,5=\pm\dfrac{1}{4}\)
\(-2x+1,5=\dfrac{1}{4}\Rightarrow-2x=1,5-0,25\Rightarrow-2x=1,25\Rightarrow x=1,25:\left(-2\right)\Rightarrow x=...\)
\(-2x+1,5=-\dfrac{1}{4}\Rightarrow-2x=-0,25-1,5\Rightarrow-2x=1,75\Rightarrow x=1,75:\left(-2\right)\Rightarrow x=...\)
\(\dfrac{3}{2}-|1.\dfrac{1}{4}+3x|=\dfrac{1}{4}\Rightarrow|1.\dfrac{1}{4}+3x|=\dfrac{3}{2}-\dfrac{1}{4}\Rightarrow|1.\dfrac{1}{4}+3x|=\dfrac{5}{4}\)
\(\Rightarrow1.\dfrac{1}{4}+3x=\pm\dfrac{5}{4}\)
\(1.\dfrac{1}{4}+3x=\dfrac{5}{4}\Rightarrow\dfrac{1}{4}+3x=\dfrac{5}{4}\Rightarrow3x=\dfrac{5}{4}-\dfrac{1}{4}\Rightarrow3x=1\Rightarrow x=3\)
\(1.\dfrac{1}{4}+3x=-\dfrac{5}{4}\Rightarrow\dfrac{1}{4}+3x=-\dfrac{5}{4}\Rightarrow3x=-\dfrac{5}{4}-\dfrac{1}{4}\Rightarrow3x=-\dfrac{3}{2}x=...\)
a: ta có: \(\left|-2x+\dfrac{3}{2}\right|=\dfrac{1}{4}\)
\(\Leftrightarrow\left[{}\begin{matrix}-2x+\dfrac{3}{2}=\dfrac{1}{4}\\-2x+\dfrac{3}{2}=-\dfrac{1}{4}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}-2x=-\dfrac{5}{4}\\-2x=-\dfrac{7}{4}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{8}\\x=\dfrac{7}{8}\end{matrix}\right.\)
b: Ta có: \(\dfrac{3}{2}-\left|\dfrac{5}{4}+3x\right|=\dfrac{1}{4}\)
\(\Leftrightarrow\left|3x+\dfrac{5}{4}\right|=\dfrac{5}{4}\)
\(\Leftrightarrow\left[{}\begin{matrix}3x+\dfrac{5}{4}=\dfrac{5}{4}\\3x+\dfrac{5}{4}=-\dfrac{5}{4}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}3x=0\\3x=-\dfrac{5}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-\dfrac{5}{6}\end{matrix}\right.\)
tính giá trị của biểu thức \(B=2x^2y+4x^3y^3+2xy^2\)
tại x=-1 y=2
giúp mình với
\(=2.\left(-1\right)^2.2+4.\left(-1\right)^3.2^3+2.\left(-1\right).2^2\\ =4+\left(-32\right)+\left(-8\right)=\left(-36\right)\)
Thay x=-1, y=2 vào B ta có:
\(B=2x^2y+4x^3y^3+2xy^2\\
=2.\left(-1\right)^2.2+4.\left(-1\right)^3.2^3+2.\left(-1\right).2^2\\
=4-32-8\\
=-36\)
tính bằng 2 cách
( 1/2 + 1/3 ) x 2/5
3/5 x 17/21 x 2/5
( 1/3 - 1/5 ) x 1/2
giúp mình bài này nha
( 1/2 + 1/3 ) x 2/5
c1 = 5/6 x 2/5 = 1/3
c2 = 1/2 x 2/5 + 1/3 x 2/5
= 1/5 + 2/15
= 1/3
3/5 x 17/21 x 2/5
c1 := 17/35 x 2/5 = 34/175
c2 : = (3/5 x 2/5) x 17/21
= 6/25 x 17/21
= 34/175?
( 1/3 - 1/5 ) x 1/2
c1 : = 2/15 x 1/2
= 1/15
c2 : = 1/3 x 1/2 - 1/5 x 1/2
= 1/6 - 1/10
= 1/15
giá trị của biểu thức 6 x 8 x 11/ 66 x4 (giải chi tiết)
A.2 B.1 C.1/3 D.1/2
giúp mình với mọi người T.T
\(\dfrac{6\times8\times11}{66\times4}=\dfrac{6\times4\times2\times11}{6\times11\times4}=2\)
phân tích đa thức thành nhân tử
x2 - 6x + 9
9y2 + 12xy + 4x2
1/25 x2 - 64y2
x3 - 8y3
(4x - 3)2 - (x+1)2
Giúp mình với mình đang cần gấp
1. (x-3)2
2. (3y+2x)2
3. (1/5x-8y)(1/5x+8y)
4. (x-2y)(x2+2xy+4y2)
5. (4x-3-x-1)(4x-3+x+1)
(3x-4)(5x-2)