x+ 3x+32x+33x+.....+349x=3100-350
tìm x
tìm x:
a)(2x-3)+(3x^2+1)-6x*(x^2-x+1)+3x^2-2x=10
b)(3x+1)*(x-2)-x*((3x-5)=-8-5x
c)(4x-3)*(16x^2+12+9)-32x^2*(2x-1)-32x^2+x=20
a: \(\left(2x-3\right)\left(3x^2+1\right)-6x\left(x^2-x+1\right)+3x^2-2x=10\)
\(\Leftrightarrow6x^3+2x-9x^2-3-6x^3+6x^2-6x+3x^2-2x=10\)
\(\Leftrightarrow-6x-3=10\)
=>-6x=13
hay x=-13/6
b: \(\Leftrightarrow3x^2-3x+x-2-3x^2+5x=-8-5x\)
=>3x-2=-5x-8
=>8x=-6
hay x=-3/4
c: \(\Leftrightarrow64x^3-27-64x^3+32x^2-32x^2+x=20\)
=>x-27=20
hay x=47
Rút gọn biểu thức sau:
A=x.(3x-4).(33x+4)-9.(x+2).(x2-2x+4)+16x
Lời giải:
$A=x[(3x)^2-4^2]-9(x^3+2^3)+16x$
$=x(9x^2-16)-9(x^3+8)+16x$
$=9x^3-16x-9x^3-72+16x$
$=-72$
\(A=x\left(3x-4\right)\left(3x+4\right)-9\left(x+2\right)\left(x^2-2x+4\right)+16x\)
\(=9x^3-16x-9x^3-72+16x\)
=-72
Cho biểu thức A = 3 + 32 + ... + 399 + 3100 .
Tìm x biết 2A + 3 = 3x
`@` `\text {Ans}`
`\downarrow`
`A = 3 + 3^2 + ... + 3^99 + 3^100`
`=> 3A = 3^2 + 3^3 + ... + 3^100 + 3^101`
`=> 3A - A = (3^2 + 3^3 + ... + 3^100 + 3^101) - (3 + 3^2 + ... + 3^99 + 3^100)`
`=> 2A = 3^101 - 3`
`=> 2A + 3 = 3^101 + 3 - 3`
`=> 2A + 3 = 3^101`
Ta có:
`2A + 3 = 3^x`
`=> x = 101.`
A=3+3^2+...+3^100
=>3*A=3^2+3^3+...+3^101
=>2A=3^101-3
=>2A+3=3^101
Theo đề, ta có: 3^x=3^101
=>x=101
Phân tích đa thức thành nhân tử:
a) x^3+6x^2+3x-10
b)x^3+3x^2-33x-35
a) \(x^3+6x^2+3x-10\)
\(=x^3-x^2+7x^2-7x+10x-10\)
\(=x^2\left(x-1\right)+7x\left(x-1\right)+10\left(x-1\right)\)
\(=\left(x-1\right)\left(x^2+7x+10\right)\)
\(=\left(x-1\right)\left(x^2+2x+5x+10\right)\)
\(=\left(x-1\right)\left(x+2\right)\left(x+5\right)\)
b) \(x^3+3x^2-33x-35\)
\(=x^3-5x^2+8x^2-40x+7x-35\)
\(=x^2\left(x-5\right)+8x\left(x-5\right)+7\left(x-5\right)\)
\(=\left(x-5\right)\left(x^2+8x+7\right)\)
\(=\left(x-5\right)\left(x^2+x+7x+7\right)\)
\(=\left(x-5\right)\left(x+1\right)\left(x+7\right)\)
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.
\(\left(-12\right)^2.x=56+10.13x\)
\(\Leftrightarrow144x=56+130x\)
\(\Leftrightarrow144x-130x=56\)
\(\Leftrightarrow14x=56\)
\(\Leftrightarrow x=4\)
tính bằng cách thuận tiện nhất :
A, 354 x 4 +354 x 5 + 354 -350
tìm x biết :
a) 19040 : x = 340
b) x - 3678 = 2541 x 4
c) x x 282 - 270 x x = 1512
d) 177 : x -96 : x + 21 : x = 6
các bạn giúp mình với mình cảm ơn
1: =354(4+5+1)-350
=3540-350
=3190
2:
a: 19040:x=340
=>x=19040/340=56
b: x-3678=2541*4
=>x-3678=10164
=>x=10164+3678=13842
c: x*282-270*x=1512
=>12x=1512
=>x=126
d: =>(177-96+21):x=6
=>102:x=6
=>x=102/6=17
Có biết 436•75+43•24+436 thuận tiện ko mấy bạn
Giải các phương trình sau:
a) x - 5(x - 2) = 6x
b) 23 + 3x2 - 32x = 48
c) (3x + 1)(x - 3)2 = (3x + 1)(2x - 5)2
d) 9x2 - 1 = (3x + 1)(4x + 1)
\(a,x-5\left(x-2\right)=6x\\ \Leftrightarrow x-5x+10-6x=0\\ \Leftrightarrow-10x+10=0\\ \Leftrightarrow x=1\\ b,2^3+3x^2-32x=48\\ \Leftrightarrow3x^2-32x+8=48\\ \Leftrightarrow3x^2-32x-40=0\)
Nghiệm xấu lắm bn
\(c,\left(3x+1\right)\left(x-3\right)^2=\left(3x+1\right)\left(2x-5\right)^2\\ \Leftrightarrow c,\left(3x+1\right)\left[\left(2x-5\right)^2-\left(x-3\right)^2\right]\\ \Leftrightarrow\left(3x+1\right)\left(2x-5-x+3\right)\left(2x-5+x-3\right)=0\\ \Leftrightarrow\left(3x+1\right)\left(x-2\right)\left(3x-8\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{3}\\x=2\\x=\dfrac{8}{3}\end{matrix}\right.\)
\(d,9x^2-1=\left(3x+1\right)\left(4x+1\right)\\ \Leftrightarrow\left(3x+1\right)\left(4x+1\right)-\left(3x-1\right)\left(3x+1\right)=0\\ \Leftrightarrow\left(3x+1\right)\left(4x+1-3x+1\right)=0\\ \Leftrightarrow\left(3x+1\right)\left(x+2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{3}\\x=-2\end{matrix}\right.\)
\(b,2x^3+3x^2-32x-48=0\\ \Leftrightarrow\left(2x^3-8x^2\right)+\left(11x^2-44x\right)+\left(12x-48\right)=0\\ \Leftrightarrow2x^2\left(x-4\right)+11x\left(x-4\right)+12\left(x-4\right)=0\\ \Leftrightarrow\left(x-4\right)\left(2x^2+11x+12\right)=0\\ \Leftrightarrow\left(x-4\right)\left[\left(2x^2+8x\right)+\left(3x+12\right)\right]=0\\ \Leftrightarrow\left(x-4\right)\left[2x\left(x+4\right)+3\left(x+4\right)\right]=0\\ \Leftrightarrow\left(x-4\right)\left(2x+3\right)\left(x+4\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=4\\x=-\dfrac{3}{2}\\x=-4\end{matrix}\right.\)
Giá trị của x để 3 x + 1 = 3 2 x - 3 là
Gọi x1,x2 là nghiệm của pt x2 - x - 1=0. không giải pt hãy CM P(x1)=P(x2) với P(x)=3x-\(\sqrt{ }\)33x+25
Tìm GTNN: (3x - 2y)/ xy - (33x+10y)/24 +2025
Biết 2 số dương x,y thỏa mãn 3x+y≤18