Ta có : VT = a x ( b - c ) + a x ( d + c )
= a x ( b - c + d + c )
= a x ( b + d ) = VP
=> a x ( b - c ) + a x ( d + c ) = a x ( b + d )
k mk nha bn
thank you very much
a(b - c) + a(d + c) = a(b + d)
=> ab - ac + ad + ac = a(b + d)
=> (ab + ad) + (-ac + ac) = a(b + d)
=> ab + ad + 0 = a(b + d)
=> ab + ad = a(b + d)