Ta có: a//b nên \(\widehat{A_2}+\widehat{B_2}=180^0\)(2 góc kề bù)
Mà \(\widehat{A_2}-\widehat{B_2}=30^0\left(gt\right)\)
\(\Rightarrow\widehat{A_2}=\left(180^0+30^0\right):2=105^0\)
Ta có: a//b(gt)
\(\Rightarrow\widehat{A_2}=\widehat{B_1}=105^0\)( 2 góc so le trong)
Ta có: \(\widehat{A_2}+\widehat{A_1}=180^0\)(2 góc kề bù)
\(\Rightarrow\widehat{A_1}=180^0-\widehat{A_2}=180^0-105^0=75^0\)
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