ax - ay + bx - by
= a(x - y) + b(x - y)
= (a + b)(x - y)
= 15.( - 4 )
= - 60
= ( x+y) . ( a+b)
= ( - 4 ) . 15
= - 60
đúng ko bn
ax - ay + bx - by
= a . ( x - y ) + b . ( x - y )
= ( a + b ) . ( x - y )
= 15 . (-4)
= -60
vậy theo bn là bao nhiêu phamtheduong
minh cho =c
cx-cy +bx-by voi c+b=155;x-y=-4
=c.(x-y)+b.(x-y)=(x-y).(c+b)=(-4).15=-60
cx-cy+bx-by voi c+b=15 ;x-y=-4 =-60
=>a.(x-y)+b.(x-y)
=a.(-4)+b.(-4)
=(-4).(a+b)
=(-4).15
=-60