Toán Lớp 6: tìm x và y biết a.(x-2).(x+7)=17 b.xy+2y+x=6 giúp mik pls

Question

Toán Lớp 6:  tìm x và y biết a.(x-2).(x+7)=17 b.xy+2y+x=6 giúp mik pls

buithaianh98 · Answer

$ a) ( x-2 ) ( x+7 ) = 17 $      $ TH1 : $  ( left[  begin{array}{l}x-2=1  x+7=17 end{array}  right. )      $ &rArr; $  ( left[  begin{array}{l}x=3  x=10 end{array}  right. )      $ TH2 : $  ( left[  begin{array}{l}x-2=17  x+7=1 end{array}  right. )      $ &rArr; $  ( left[  begin{array}{l}x=19  x=-6 end{array}  right. )      $ TH3 : $  ( left[  begin{array}{l}x-2=-1  x+7=-17 end{array}  right. )      $ &rArr; $  ( left[  begin{array}{l}x=1  x=-24 end{array}  right. )      $ TH4 : $  ( left[  begin{array}{l}x-2=-17  x+7=-1 end{array}  right. )      $ &rArr; $  ( left[  begin{array}{l}x=-15  x=-8 end{array}  right. )      $ b) xy + 2y + x = 6 $      $ &rArr; ( xy + x ) + 2y + 2 = 8 $       $ x ( y + 1 ) + 2 ( y + 1 ) = 8 $     $ &rArr; ( x + 2 ) ( y + 1 ) = 8 $     $ ( x+2 ; y+1 ) = ( 8;1 ) ; ( 1;8 ) ; ( 2;4 ) ; ( 4;2 ) $     $ ( x;y ) = ( 6;0 ) ; ( -1;7 ) ; ( 0;3 ) ; ( 2;1 ) $