tìm x:5x+2016=2006
2(x-4)-(x+5)=-13
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tìm x:5x+2016=2006
2(x-4)-(x+5)=-13
5x+2016 = 2006 => 5x = 2006 - 2016 = -10 => x = -10 : 5 = -2
2(x-4)-(x+5) = 2x-8-x-5 = (2x-x)-(8+5) = x-13 = -13 => x = -13+13 = 0
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\(5x+2016=2006\)
\(\Rightarrow5x=2006-2016\)
\(\Rightarrow5x=-10\)
\(\Rightarrow x=-10:5\)
\(\Rightarrow x=-2\)
\(2\left(x-4\right)-\left(x+5\right)=-13\)
\(\Rightarrow2x-8-x-5=-13\)
\(\Rightarrow x=-13+8+5\)
\(\Rightarrow x=0\)
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tìm tổng của các hệ số
B(x)=(3x^3-5x^2+x+2)^2016
C(x)=(x^5-7x^2+x+5)^2015+(x^4+9x^2+x-12)^2016
Tìm x biết : -3 phần x+5=6 phần -1-5x. Tính : 0,75+11 phần 13+0,25 -24 phần 13+2015 phần 2016 ;
bai 1 Tim x,y
a, (x-3)x+3 =(x-3)x+13
b,\(\frac{5x-1}{3}=\frac{7y-6}{5}=\frac{5x-4y-7}{4x}\)
c,|x+5|=(3y-4)2016
Tìm đa thức dư khi chia đa thức x(x+1)(x+2)(x+3)(x+4)+2016 cho đa thức x^2+5x+5
\(x\left(x+1\right)\left(x+2\right)\left(x+3\right)\left(x+4\right)+2016\)
\(=x\left(x^2+5x+4\right)\left(x^2+5x+6\right)+2016\)
\(=x\left(x^2+5x+5-1\right)\left(x^2+5x+5+1\right)+2016\)
\(=x\left[\left(x^2+5x+5\right)-1\right]+2016\)
\(=x\left(x^2+5x+5\right)-x+2016\)
Đáp số : Dư \(-x+2016\)
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tìm x,biết 5x-4/5=x+13/15
\(5x-\dfrac{4}{5}=x+\dfrac{13}{15}\)
\(\Rightarrow5x-x=\dfrac{13}{15}+\dfrac{4}{5}\)
\(\Rightarrow4x=\dfrac{13}{15}+\dfrac{12}{15}\)
\(\Rightarrow4x=\dfrac{25}{15}\)
\(\Rightarrow4x=\dfrac{5}{3}\)
\(\Rightarrow x=\dfrac{5}{3}:4\)
\(\Rightarrow x=\dfrac{5}{12}\)
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5x-4/5=x+13/15
<=>5x-x=13/15+4/5
<=>4x=5/3
<=>x=5/12
vậy ...
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|x+5|+(3y-4)^2016=0
(5x-y)^2016+|x^2-4|^2017<=0
(2x-1)^2014+(y-2/5)^2016+|x+y+z|=0
|x-1|+|x-2|+|y-3|+|x-4|=3
8 tháng 9 2021 lúc 14:22
Bài 4: Tìm x, biết:
a) 3(2x – 3) + 2(2 – x) = –3 ; b) x(5 – 2x) + 2x(x – 1) = 13 ;
c) 5x(x – 1) – (x + 2)(5x – 7) = 6 ; d) 3x(2x + 3) – (2x + 5)(3x – 2) = 8 ;
e) 2(5x – 8) – 3(4x – 5) = 4(3x – 4) + 11; f) 2x(6x – 2x 2 ) + 3x 2 (x – 4) = 8.
\(a,3\left(2x-3\right)+2\left(2-x\right)=-3\\ \Leftrightarrow6x-9+4-2x=-3\\ \Leftrightarrow4x=2\\ \Leftrightarrow x=\dfrac{1}{2}\\ b,x\left(5-2x\right)+2x\left(x-1\right)=13\\ \Leftrightarrow5x-2x^2+2x^2-2x=13\\ \Leftrightarrow3x=13\\ \Leftrightarrow x=\dfrac{13}{3}\\ c,5x\left(x-1\right)-\left(x+2\right)\left(5x-7\right)=6\\ \Leftrightarrow5x^2-5x-5x^2-3x+14=6\\ \Leftrightarrow-8x=-8\\ \Leftrightarrow x=1\\ d,3x\left(2x+3\right)-\left(2x+5\right)\left(3x-2\right)=8\\ \Leftrightarrow6x^2+9x-6x^2-11x+10=8\\ \Leftrightarrow-2x=-2\\ \Leftrightarrow x=1\)
\(e,2\left(5x-8\right)-3\left(4x-5\right)=4\left(3x-4\right)+11\\ \Leftrightarrow10x-16-12x+15=12x-16+11\\ \Leftrightarrow-14x=-4\\ \Leftrightarrow x=\dfrac{2}{7}\\ f,2x\left(6x-2x^2\right)+3x^2\left(x-4\right)=8\\ \Leftrightarrow12x^2-4x^3+3x^3-12x^2=8\\ \Leftrightarrow-x^3-8=0\\ \Leftrightarrow-\left(x^3+8\right)=0\\ \Leftrightarrow-\left(x+2\right)\left(x^2-2x+4\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=-2\\x\in\varnothing\left(x^2-2x+4=\left(x-1\right)^2+3>0\right)\end{matrix}\right.\)
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Bài 4:
a: Ta có: \(3\left(2x-3\right)-2\left(x-2\right)=-3\)
\(\Leftrightarrow6x-9-2x+4=-3\)
\(\Leftrightarrow4x=2\)
hay \(x=\dfrac{1}{2}\)
b: Ta có: \(x\left(5-2x\right)+2x\left(x-1\right)=13\)
\(\Leftrightarrow5x-2x^2+2x^2-2x=13\)
\(\Leftrightarrow3x=13\)
hay \(x=\dfrac{13}{3}\)
c: Ta có: \(5x\left(x-1\right)-\left(x+2\right)\left(5x-7\right)=6\)
\(\Leftrightarrow5x^2-5x-5x^2+7x-10x+14=6\)
\(\Leftrightarrow-8x=-8\)
hay x=1
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a/ \(3\left(2x-3\right)+2\left(2-x\right)=-3\)
\(\Leftrightarrow6x-9+4-2x=-3\)
\(\Leftrightarrow4x=2\)
\(\Leftrightarrow x=\dfrac{1}{2}\)
Vậy: \(x=\dfrac{1}{2}\)
===========
b/ \(x\left(5-2x\right)+2x\left(x-1\right)=13\)
\(\Leftrightarrow5x-2x^2+2x^2-2x=13\)
\(\Leftrightarrow3x=13\)
\(\Leftrightarrow x=\dfrac{13}{3}\)
Vậy: \(x=\dfrac{13}{3}\)
==========
c/ \(5x\left(x-1\right)-\left(x+2\right)\left(5x-7\right)=6\)
\(\Leftrightarrow5x^2-5x-5x^2+7x-10x+14=6\)
\(\Leftrightarrow-8x=-8\)
\(\Leftrightarrow x=1\)
Vậy: \(x=1\)
==========
d/ \(3x\left(2x+3\right)-\left(2x+5\right)\left(3x-2\right)=8\)
\(\Leftrightarrow6x^2+9x-6x^2+4x-15x+10=8\)
\(\Leftrightarrow-2x=-2\)
\(\Leftrightarrow x=1\)
Vậy: \(x=1\)
==========
e/ \(2\left(5x-8\right)-3\left(4x-5\right)=4\left(3x-4\right)+11\)
\(\Leftrightarrow10x-16-12x+15=12x-16+11\)
\(\Leftrightarrow-14x=-4\)
\(\Leftrightarrow x=\dfrac{2}{7}\)
Vậy: \(x=\dfrac{2}{7}\)
==========
f/ \(2x\left(6x-2x^2\right)+3x^2\left(x-4\right)=8\)
\(\Leftrightarrow12x^2-4x^3+3x^3-12x^2=8\)
\(\Leftrightarrow-x^3=8\)
\(\Leftrightarrow x=-2\)
Vậy: \(x=-2\)
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a)Chứng minh D chia hết cho 126 biết D = 5 + 5^2 + 5^3 + ... + 5^2016.
b) Tìm x thuộc N biết 4d + 5 = 5x
c) Tìm STN a biết a chia 11 dư 7, chia 13 dư 10.