(3x+5)(5-3x)+3(x+2)^2=20
Giúp mk nha!!!
4.(5x-20)+3x2-12x=0
5.(1-x)-3x2+3x=0
6)4x+20-(x+5)2=0
giải dùm mk nha
Bài 4 :
\(\left(5x-20\right)+\left(3x^2-12x\right)=0\)
\(\Leftrightarrow5\left(x-4\right)+3x\left(x-4\right)=0\)
\(\Leftrightarrow\left(x-4\right)\left(5+3x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-4=0\\5+3x=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=4\\x=-\dfrac{5}{3}\end{matrix}\right.\)
Vậy \(x=4\) hoặc \(x=-\dfrac{5}{3}\)
Bài 5 :
\(\left(1-x\right)-3x^2+3x=0\)
\(\Leftrightarrow\left(1-x\right)-\left(3x^2-3x\right)=0\)
\(\Leftrightarrow\left(1-x\right)-3x\left(x-1\right)=0\)
\(\Leftrightarrow\left(1-x\right)+3x\left(1-x\right)=0\)
\(\Leftrightarrow\left(1-x\right)\left(1+3x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}1-x=0\\1+3x=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=1\\x=-\dfrac{1}{3}\end{matrix}\right.\)
Vậy \(x=1\) hoặc \(x=-\dfrac{1}{3}\)
Bài 6 :
\(\left(4x+20\right)-\left(x+5\right)^2=0\)
\(\Leftrightarrow4\left(x+5\right)-\left(x+5\right)^2=0\)
\(\Leftrightarrow\left(x+5\right)\left(4-x-5\right)=0\)
\(\Leftrightarrow\left(x+5\right)\left(-x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+5=0\\-x-1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=-5\\x=-1\end{matrix}\right.\)
Vậy \(x=-5\) hoặc \(x=-1\)
a,(x+8)-11=20-15
b,2x-(3+x)=5-7
c,(3x-2⁴)×7⁵=2×7⁶
giúp mk với mk cần gấp
a)\(\left(x+8\right)-11=20-15\)
\(\left(x+8\right)-11=5\)
\( x+8=5+11\)
\(x+8=16\)
\(x=8\)
b) \(2x-\left(3+x\right)=5-7\)
\(2x-\left(3+x\right)=-2\)
\(2x-3-x=-2\)
\(x=1\)
c) \( \left(3x-2^4\right)\times7^5=2\times7^6\)
\(3x-2^4=2\times\left(7^6:7^5\right) \)
\(\left(3x-2^4\right)=2\times7^2\)
\(3x-2^4=2\times49\)
\(3x-16=98\)
\(3x=114\)
\(x=38\)
bài 1 ; tìm x bt
a,3.(x+3)-2.(x-5)=11
b,14-4./x/=-6
bài 2 tìm x,y nguyên biết
a,(x-2).(6+y)=(-19)
b,2xy - 3x +20= 0
c, xy+2y+3x+15=0
giúp mk nha, mk cần gấp
a, 3(x+3)-2(x-5)=11
=> 3x+9-2x+10=11
=> 3x-2x=11-10-9
=> x=-8
Vậy.........
b, 14-4|x|=-6
=> -4|x|=8
=> |x|=-2(VL vì trị tuyệt đối luôn lớn hơn hoặc = 0)
Vậy......
5^x-2=125
3^x+4=243
x+5=20-(12-7)
579-3x=3^2.2^4
15-x=8-(-12)
giúp mk voi 10 gio mk can nha
\(a,5^{x-2}=125\)
\(\Rightarrow5^{x-2}=5^3\)
\(\Rightarrow x-2=3\)
\(\Rightarrow x=5\)
\(b,3^{x+4}=243\)
\(\Rightarrow3^{x+4}=3^5\)
\(\Rightarrow x+4=5\)
\(\Rightarrow x=1\)
\(5^{x-2}=125\)
\(\Rightarrow5^{x-2}=5^3\)
\(\Rightarrow x-2=3\)
\(\Rightarrow x=3+2\)
\(\Rightarrow x=5\)
\(5^{x-2}=125\)
\(\Rightarrow5^{x-2}=5^3\)
\(\Rightarrow x-2=3\)
\(x=5\)
\(3^{x+4}=243\)
\(\Rightarrow3^{x+4}=3^5\)
\(\Rightarrow x+4=5\)
\(\Rightarrow x=1\)
giải giúp mk nha
a) |3x-2|-5=7
b)| 3x-1|-|x+2|=0
c)|3x-3|=x-3
d)4-|4x+3|=5x
a) |3x - 2| - 5 = 7
=> |3x - 2| = 7 + 5
=> |3x - 2| = 12
=> \(\orbr{\begin{cases}3x-2=12\\3x-2=-12\end{cases}}\)
=> \(\orbr{\begin{cases}3x=14\\3x=-10\end{cases}}\)
=> \(\orbr{\begin{cases}x=\frac{14}{3}\\x=-\frac{10}{3}\end{cases}}\)
b) |3x - 1| - |x + 2| = 0
=> |3x - 1| = |x + 2|
=> \(\orbr{\begin{cases}3x-1=x+2\\3x-1=-x-2\end{cases}}\)
=> \(\orbr{\begin{cases}2x=3\\4x=-1\end{cases}}\)
=> \(\orbr{\begin{cases}x=\frac{3}{2}\\x=-\frac{1}{4}\end{cases}}\)
c) |3x - 3| = x - 3
ĐKXĐ: x - 3 \(\ge\)0 <=> x \(\ge\)3
=> \(\orbr{\begin{cases}3x-3=x-3\\3x-3=3-x\end{cases}}\)
=> \(\orbr{\begin{cases}2x=0\\4x=6\end{cases}}\)
=> \(\orbr{\begin{cases}x=0\left(ktm\right)\\x=\frac{3}{2}\left(ktm\right)\end{cases}}\)
4) 4 - |4x + 3| = 5x
=> |4x + 3| = 4 - 5x
ĐKXĐ: 4 - 5x \(\ge\)0 <=> x \(\le\)4/5
=> \(\orbr{\begin{cases}4x+3=4-5x\\4x+3=5x-4\end{cases}}\)
=> \(\orbr{\begin{cases}9x=1\\-x=-7\end{cases}}\)
=> \(\orbr{\begin{cases}x=\frac{1}{9}\left(tm\right)\\x=7\left(ktm\right)\end{cases}}\)
Tìm x, biết:
a) 5-|x+2|=3-x
b) 3x+|5-x|=11
c) |x-5|+|3x+2|=15
d) 3x-|x+2|+|5-2x|=1
e) |x+2|+|5-3x|=x+6
g) |x-3|+|5-x|=2 và x thuộc Z
h) |x+7|+|x-1|=8 và x thuộc Z
Mn giúp mk nhanh nha mai là mk phải nạp rồi cảm ơn
Các bn giúp mk nha , mk sẽ tick cho >.<
Rút gọn biểu thức
a) A = 5.(x+2) - /3x-6/
b) B = 17 -2./x+2/
c) C = 3x+1+/x-3/
d) D = 3x-5 + /2x+1/
(x-2/5).(x+2/7)>0
( 2x-1/2).(3x-1/3)<0
x+3/2 phần x-2/3 <0
Tìm x
Các bạn giúp mk nha mk cần gấp
a: Ta có: \(\left(x-\dfrac{2}{5}\right)\left(x+\dfrac{2}{7}\right)>0\)
\(\Leftrightarrow\left[{}\begin{matrix}x>\dfrac{2}{5}\\x< -\dfrac{2}{7}\end{matrix}\right.\)
Tính hiệu của f(x) và g(x) bt:
f(x)=7x^6 - 6x^5 + 5x^4 - 4x^3 + 3x^2 - 2 x + 1
g(x)=x -2x^2 + 3x^3 - 4x^4 + 5x^5 - 6x^6
MN GIÚP MK VS NHA MK ĐG CẦN GẤP AI NHANH MK TICK CHO NHA
ta có: f(x) + g(x) = ( 7 x^6 - 6x ^5 +5x^4 -4x^3 +3x^2 -2x +1) - ( x - 2x^2 +3x^3 - 4x^4 + 5x^5 - 6x^6)
\(=7x^6-6x^5+5x^4-4x^3+3x^2-2x+1-x+2x^2-3x^3+4x^4-5x^5+6x^6\)
\(=\left(7x^6+6x^6\right)-\left(6x^5+5x^5\right)+\left(5x^4+4x^4\right)-\left(4x^3+3x^3\right)+\left(3x^2+2x^2\right)-\left(2x+x\right)+1\)
\(=13x^6-11x^5+9x^4-7x^3+5x^2-3x+1\)
Chúc bn học tốt !!!!!!
Uhhhhhhhhhhhhhhhhhhhhhhhhhh😥😥😥😥😥😥😥😥😥😥😥????????????...............