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Có 2x +7= 2x-4+11
=> 2x-4\(⋮\)x-4 =>2x+7\(⋮\)x-4 => 11\(⋮\)x-4 <=> x-4 \(\in\)Ư(11)
Mà Ư(11)=1,-1,11,-11 \(\Rightarrow\)x-4\(\in\)1,-1,-11,11 \(\Rightarrow\)x\(\in\)5,3,-7,15
\(=\dfrac{2^{19}\cdot3^9\cdot5+2^{18}\cdot3^9\cdot5}{2^{19}\cdot3^9-2^{20}\cdot3^{10}}\)
\(=\dfrac{2^{18}\cdot3^9\cdot5\left(2+1\right)}{2^{19}\cdot3^9\left(1-2\cdot3\right)}=\dfrac{1}{2}\cdot\dfrac{5\cdot3}{-5}=-\dfrac{3}{2}\)
\(A=\dfrac{2^{19}\cdot27^3\cdot5-15\cdot\left(-4\right)^9\cdot9^4}{6^9\cdot2^{10}-\left(-12\right)^{10}}\)
\(A=\dfrac{2^{19}\cdot\left(3^3\right)^3\cdot5-3\cdot5\cdot-\left(2^2\right)^9\cdot\left(3^2\right)^4}{2^9\cdot3^9\cdot2^{10}-\left(2^2\right)^{10}\cdot3^{10}}\)
\(A=\dfrac{2^{19}\cdot3^9\cdot5+3^9\cdot2^{18}\cdot5}{2^{19}\cdot3^9-2^{20}\cdot3^{10}}\)
\(A=\dfrac{2^{18}\cdot3^9\cdot5\cdot\left(2+1\right)}{2^{19}\cdot3^9\cdot\left(1-2\cdot3\right)}\)
\(A=\dfrac{1\cdot1\cdot5\cdot3}{2\cdot1\cdot-5}\)
\(A=-\dfrac{1}{2}\cdot3\)
\(A=-\dfrac{3}{2}\)
d: =-100+720/718
=-35540/359
e: \(=5^3-9\cdot16=125-144=-19\)
f: \(=8\cdot9-7^2+7=72+7-49=30\)
Bài 1:
(x-6)^2020+2(y+3)^2022=0
=>x-6=0 và y+3=0
=>x=6 và y=-3
2:
a: Gọi d=ƯCLN(7n+4;9n+5)
=>63n+36-63n-35 chia hết cho d
=>1 chia hết cho d
=>d=1
=>PSTG
b: Gọi d=ƯCLN(n^3+3n;n^4+3n^2+1)
=>n^3+3n chia hết cho d và n^4+3n^2+1 chia hết cho d
=>n^4+3n^2-n^4-3n^2-1 chia hết cho d
=>-1 chia hết cho d
=>d=1
=>PSTG
c: Gọi d=ƯCLN(12n+1;30n+2)
=>60n+5-60n-4 chia hết cho d
=>1 chia hết cho d
=>d=1
=>PSTG
1.
$(a+b+c)-(a-b+c)=a+b+c-a+b-c=(a-a)+(b+b)+(c-c)=0+2b+0=2b$
2.
$(a-b+c)-(a-b+c)=0$
3.
$(a+b+c)-(b-a+c)=a+b+c-b+a-c=(a+a)+(b-b)+(c-c)=2a+0+0=2a$
4.
$(a-c)-(d+b+a+c)=a-c-d-b-a-c=(a-a)+(-c-c)-d-b=0-2c-d-b=-2c-d-b$
5.
$(a+d-c)-(a+b-c)=a+d-c-a-b+c=(a-a)+(-c+c)+d-b=0+0+d-b=d-b$
6.
$(a-b+c+d)+(a+c-d-b)=a-b+c+d+a+c-d-b$
$=(a+a)+(-b-b)+(c+c)+(d-d)=2a-2b+2c$
7.
$(a+d-c)+(a-b+c)=a+d-c+a-b+c=(a+a)+d+(-c+c)=2a+d$