[TEX]a, \ 5\hat{M}=3\hat{N} \Rightarrow \hat{M}=\frac{3}{5}\hat{N}[/TEX]
Thế vào [TEX]7\hat{M} -4\hat{N} =15^o [/TEX] , ta được:
[TEX]7.\frac{3}{5}\hat{N} -4\hat{N} =15^o \Rightarrow \frac{1}{5}\hat{N}=15^o \Rightarrow \hat{N}=75^o [/TEX]
[TEX]\Rightarrow \hat{M}=\frac{3}{5}.75^o=45^o \Rightarrow \hat{P}=180^o-75-45=60^o[/TEX]
b, N^+P^=180o−80o=100o⇒N^=2100o+30o=65o⇒P^=65o−40o=25o