3^x+2-3^x=10^2-28
tìm x biết: 3^x+2 - 3^x = 10^2 - 28
1, 4x^3+5x^2+10-12
2, (6x+7)^2(3x+4)(x+1)-6
3, (x^2-6x+5)(x^2-10+21)-20
4, (x^2+x-2)(x^2+9x+18)-28
1) \(4x^3+5x^2+10x-12\)
\(=4x^3-3x^2+8x^2-6x+16x-12\)
\(=x^2\left(4x-3\right)+2x\left(4x-3\right)+4\left(4x-3\right)\)
\(=\left(4x-3\right)\left(x^2+2x+4\right)\)
Đề bài : Phân tích các đa thức sau thành nhân tử
1 tim cac so nguyen x,y biet x/7=6/21 -5/y=20/28 1/2=x/12 x/8=-28/32 3/y=12/24 3/4=15/y 2 viet 3 phan so bang phan so -10/15
Tìm x biết
10 . (3x - 2) - 32 x 23 = 28
10 . (3x - 2) - 32 . 23 = 28
=> 10 . (3x - 2) - 9 . 8 = 28
=> 10 . (3x - 2) - 72 = 28
=> 10 . (3x - 2) = 100
=> 3x - 2 = 10
=> 3x = 12
=> x = 12 : 3 = 4
Vậy x = 4
\(10\left(3x-2\right)-9\cdot8=28\)
\(10\left(3x-2\right)-72=28\)
\(10\left(3x-2\right)=28+72\)
\(10\left(3x-2\right)=100\)
\(3x-2=100:10\)
\(3x-2=10\)
\(3x=12\)
\(x=4\)
10.(3x-2)-9.8=28
10.(3x-2)-9+28:8
10.(3x-2)-9=7/2
10.(3x-2)=7/2+9
10.(3x-2)=25/2
3x-2=25/2:10
3x-2=5/4
3x=5/4+2
3x=13/4
x=13/4:3
x=13/12
Tìm các số x và y biết
1) 4/x= y/21=28/49. 2) x/2=3/y. 3)42/54=7/x
4) 2/3 =y/15. 5)6/10 = 3/x =y/20
\(\dfrac{4}{x}=\dfrac{y}{21}=\dfrac{28}{49}=\dfrac{28:7}{49:7}=\dfrac{4}{9}\\ Vậy:x=\dfrac{4.9}{4}=9\\ y=\dfrac{4.21}{9}=\dfrac{28}{3}\)
\(\dfrac{x}{2}=\dfrac{3}{y}\\ \Leftrightarrow x.y=2.3=6\\ Vậy:\left[{}\begin{matrix}\left(x;y\right)=\left(1;6\right)=\left(6;1\right)\\\left(x;y\right)=\left(2;3\right)=\left(3;2\right)\end{matrix}\right.\)
\(3,\\ \dfrac{42}{54}=\dfrac{42:6}{54:6}=\dfrac{7}{9}\\ \dfrac{42}{54}=\dfrac{7}{x}=\dfrac{7}{9}\\ Vậy:x=\dfrac{7.9}{7}=9\)
10 - [ ( 82 - 48 ) x 5 + ( 23 x 10 + 8 ) ] : 28
10 - [ ( 82 - 48 ) x 5 + ( 23 x 10 + 8 ) ] : 28
= 10 - [ ( 64 - 48 ) x 5 + ( 8 x 10 + 8 ) ] :28
=10 - [ 16 x 5 + 88 ] :28
=10 - 168 : 28
=10 - 6 = 4
Ý kiến của mình ạ <333
= 10 - [( 64 - 48 ) . 5 + ( 8 . 10 + 8 ) ] : 28
= 10 - [16 . 5 + ( 80 + 8 ) ] : 28
= 10 - [80 + 88] :28
= 10 - 168 : 28
= 10 - 6
= 4
Bài 1: Tìm số nguyên x, biết:
a)\(\dfrac{6}{x-3}\) = \(\dfrac{2}{3}\)
b) \(\dfrac{14}{13}\) = \(\dfrac{-28}{10-x}\)
c) \(\dfrac{1}{5}\) = \(\dfrac{x:4-1}{10}\)
d) \(\dfrac{x}{4}\)= \(\dfrac{1}{x}\)
e) \(\dfrac{x-2}{50}\) = \(\dfrac{2}{x-2}\)
giúp ưm
a: =>x-3=9
=>x=12
b: =>10-x=-26
=>x=36
c: =>x:4-1=2
=>x:4=3
=>x=12
d: =>x^2=4
=>x=2 hoặc x=-2
e: =>(x-2)^2=100
=>x-2=10 hoặc x-2=-10
=>x=12 hoặc x=-8
Tìm số nguyên x , biết
10 - 2 ( 4 - 3x) = -4
c) -12 + 3(-x + 7 ) = -18
-45 : 5 . (-3 - 2x) = 3
3x - 28 = x +36
(-12)2 . x = 56 + 10 . 13x
a.
\(10-2\left(4-3x\right)=-4\)
\(\Leftrightarrow2\left(4-3x\right)=10+4\)
\(\Leftrightarrow2\left(4-3x\right)=14\)
\(\Leftrightarrow4-3x=7\)
\(\Leftrightarrow3x=-3\)
\(\Leftrightarrow x=-1\)
b.
\(-12+3\left(-x+7\right)=-18\)
\(\Leftrightarrow3\left(-x+7\right)=-18+12=-6\)
\(\Leftrightarrow-x+7=-6:3=-2\)
\(\Leftrightarrow x=9\)
c.
\(-45:5.\left(-3-2x\right)=3\)
\(\Leftrightarrow-9.\left(-3-2x\right)=3\)
\(\Leftrightarrow-3-2x=-\dfrac{1}{3}\)
\(\Leftrightarrow2x=-\dfrac{8}{3}\)
\(\Leftrightarrow x=-\dfrac{4}{3}\notin Z\left(loại\right)\)
Câu này em ghi sai đề?
d.
\(3x-28=x+36\)
\(\Leftrightarrow2x=28+36\)
\(\Leftrightarrow2x=64\)
\(\Leftrightarrow x=32\)
e.
\(\left(-12\right)^2.x=56+10.13x\)
\(\Leftrightarrow144x=56+130x\)
\(\Leftrightarrow144x-130x=56\)
\(\Leftrightarrow14x=56\)
\(\Leftrightarrow x=4\)
\(\dfrac{x-1}{29}+\dfrac{x-2}{28}+\dfrac{x-3}{27}+\dfrac{x}{10}-6=0\)