Question

tìm số nguyên x bt

1) \(1+x-2\left(5+3x\right)=4-5x\)

2)\(\left(2x-3\right)^3=-\left(-6^2\right)-\left(-2\right)^3+\left(-1\right)^{2011}\)

Answer 1

\(1+x-2\left(5+3x\right)=4-5x\)

\(1+x-10-6x=4-5x\)

\(x-6x+5x=4+10-1\)

\(0x=13\Leftrightarrow x=0\)

Answer 2

1) Ta có: \(1+x-2.\left(5+3x\right)=4-5x\)

        \(\Leftrightarrow1+x-10-6x=4-5x\)

        \(\Leftrightarrow x-6x+5x=4-1+10\)

        \(\Leftrightarrow0x=13\)( vô nghiệm )

Vậy \(S=\left\{\varnothing\right\}\)

Answer 3

\(1/1+x-2.\left(5+3x\right)=4-5x\)

\(=1+x-10-6x=4-5x\)

\(=>x+5x-6x=4+10-1=13\)

\(=>0=13\left(vl\right)\)

\(2/\left(2x-3\right)^3=-\left(-6^2\right)-\left(-2\right)^3+\left(-1\right)^{2011}\)

\(=>\left(2x-3\right)^3=36+8-1=43\)

(Lập phương của 1 hiệu: (a - b)³ = a³ - 3a²b + 3ab² - b³) sd hđt nhé :

=>2x³-3.2x².3-3.2x.3³-3³=43

=>2x³-2x².9-2x.81-27=43

đến đây thì dễ r