-45:5*(-3-2x)=3
=> -9*(-3-2x)=3
=> -9*(-3)-(-9)*2x=3
=> 27-(-18)x=3
=> 27+18x=3
=> 18x=3-27
=> 18x=-24
=> x=-24/18
=> x=(-4)/3
\(-45\div5\times\left(-3-2x\right)=3\)
\(\Rightarrow-45\div\left(-15-10x\right)=3\)
\(\Rightarrow-15-10x=-45\div3\)
\(\Rightarrow-15-10x=-15\)
\(\Rightarrow-10x=-15+15\)
\(\Rightarrow-10x=0\)
\(\Rightarrow x=0\div\left(-10\right)\)
VẬY:\(x=0\)