5(3-2x)+5(x+4)6-4x 
= 15-10x++30x+120-4x
= (15+120)+(-10x+30x-4x)
= 135+16x

5(3-2x)+5(x+4)6-4x 

= 15-10x++30x+120-4x

= (15+120)+(-10x+30x-4x)

= 135+16x

\(ax-b>bx+a\)

\(\Leftrightarrow ax-a=bx+b\)

\(\Leftrightarrow a\left(x-1\right)-b\left(x-1\right)>0\)

\(\left(x-1\right)\left(a-b\right)>0\)

\(a^3+b^3-c^3+3abc\)

\(=\left(a+b\right)^3-3ab\left(a+b\right)-c^3+3abc\)

\(=\left(a+b-c\right)^3+3c\left(a+b\right)\left(a+b-c\right)-3ab\left(a+b-c\right)\)

\(=\left(a+b-c\right)\left(a^2+b^2+c^2-ab+bc+ca\right)=0\)

\(\Leftrightarrow a+b-c=0\)

\(\Leftrightarrow a+b=c\)

\(P=\left(\frac{a+b}{c}\right)^{10}=1^{10}=1\)

Ta có

 \(x\left(1+2x\right)-2\left(2x+1\right)=0\)

\(\Leftrightarrow\left(x-2\right)\left(2x+1\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x-2=0\\2x+1=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=2\\x=-\frac{1}{2}\end{cases}}\)

Trả lời:

\(x\left(1+2x\right)-2\left(2x+1\right)=0\)

\(\Leftrightarrow\left(2x+1\right)\left(x-2\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}2x+1=0\\x-2=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-\frac{1}{2}\\x=2\end{cases}}}\)

Vậy x = - 1/2; x = 2 là nghiệm của pt.

A=x2y−y+xy2−xx2y−y+xy2−x

A=(x2y−y)+(xy2−x)(x2y−y)+(xy2−x)

A=y(x2−1)+x(y2−1)y(x2−1)+x(y2−1)

A=y(x-1)(x+1)+x(y-1)(y+1)

thay x=-5 và y=2 ta có:

A=2(-5-1)(-5+1) - 5(2-1)(2+1)

A=2 . (-6) . (-4) - 5 . 3 

A=48 - 15

A=  33

\(x^2.y-y+x.y^2-x=\left(-5\right)^2.2-2+\left(-5\right).2^2-\left(-5\right)\)

\(=25.2-2-5.4+5=50-2-20+5=33\)

Hằng đẳng thức: a^n - b^n = (a-b)[a^(n-1).b + a(n-2).b² +..+ b^(n-1)] = (a-b).p 

* 5^2n - 2^n = 25^n - 2^n = (25-2)p = 23p => 5.5^2n - 5.2^n = 5.23.p 
=> 5^(2n+1) - 5.2^n = 5.23p chia hết cho 23 

* 2^(n+4) + 2^(n+1) = 2^n.2^4 + 2^n.2 = 2^n(2^4 + 2) = 18.2^n = 23.2^n - 5.2^n 

Vậy: 5^(2n+1) + 2^(n+4) + 2^(n+1) = 5^(2n+1) - 5.2^n + 23.2^n chia hết cho 23 .

\(\left|3-2x\right|=3x-7\)

Trường hợp 1: \(3-2x\ge0\Leftrightarrow x\le\frac{3}{2}\)

\(3-2x=3x-7\Leftrightarrow-5x=-10\Leftrightarrow x=2\)(Loại)

Trường hợp 2: \(3-2x< 0\Leftrightarrow x>\frac{3}{2}\)

\(3-2x=-\left(3x-7\right)\Leftrightarrow3-2x=7-3x\Leftrightarrow x=4\)(Thỏa mãn)

\(\left|3x\right|=7\)

Trường hợp 1: \(3x=7\Leftrightarrow x=\frac{7}{3}\)

Trường hợp 2: \(3x=-7\Leftrightarrow x=\frac{-7}{3}\)