Bài 4:
a: (2x-5)+17=6
=>2x-5=6-17=-11
=>2x=-6
=>\(x=-\dfrac{6}{2}=-3\)
b: \(10-2\left(4-3x\right)=-4\)
=>\(2\left(4-3x\right)=10+4=14\)
=>4-3x=7
=>3x=4-7=-3
=>\(x=-\dfrac{3}{3}=-1\)
c: \(-12+3\left(-x+7\right)=-18\)
=>\(3\left(7-x\right)=-18+12=-6\)
=>7-x=-2
=>x=7+2=9
d: \(-45:5\left(-3-2x\right)=3\)
=>\(-9\left(-2x-3\right)=3\)
=>9(2x+3)=3
=>\(2x+3=\dfrac{1}{3}\)
=>\(2x=\dfrac{1}{3}-3=-\dfrac{8}{3}\)
=>\(x=-\dfrac{8}{3}:2=-\dfrac{4}{3}\)
e: \(3x-28=x+36\)
=>3x-x=28+36
=>2x=64
=>\(x=\dfrac{64}{2}=32\)
f: \(\left(-12\right)^x\cdot x=56+10\cdot13x\)
=>\(144x-130x=56\)
=>14x=56
=>x=4
Bài 5:
a: x(x+7)=0
=>\(\left[{}\begin{matrix}x=0\\x+7=0\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}x=0\\x=-7\end{matrix}\right.\)
b: (x+12)(x-3)=0
=>\(\left[{}\begin{matrix}x+12=0\\x-3=0\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}x=-12\\x=3\end{matrix}\right.\)
c: (-x+5)(3-x)=0
=>\(\left[{}\begin{matrix}5-x=0\\3-x=0\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}x=5\\x=3\end{matrix}\right.\)
d: (x-1)(x+2)(-x-3)=0
=>(x-1)(x+2)(x+3)=0
=>\(\left[{}\begin{matrix}x-1=0\\x+2=0\\x+3=0\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}x=1\\x=-2\\x=-3\end{matrix}\right.\)
