\(1,53kg=1kg53g\)

không có gì

\(a,\left(2\times x-40\right):10=-55\)

\(2\times x-40=-55\times10\)

\(2\times x-40=-550\)

\(2\times x=-550+40\)

\(2\times x=-510\)

\(x=-510:2\)

\(\Rightarrow x=-255\)

\(b,\left(2\times x+15\right):5=-40\)

\(2\times x+15=-40\times5\)

\(2\times x+15=-200\)

\(2\times x=-200-15\)

\(2\times x=-215\)

\(x=-215:2\)

\(\Rightarrow x=-\dfrac{215}{2}\)

\(c,\left(2\times x-72\right):8=25\)

\(2\times x-72=25\times8\)

\(2\times x-72=200\)

\(2\times x=200+72\)

\(2\times x=272\)

\(x=272:2\)

\(\Rightarrow x=136\)