Đáp án:
Giải thích các bước giải:
a, VT=a.(b−c)+c.(a−b)=ab−ac+ac−bc=b(a−c)=VPVT=a.(b−c)+c.(a−b)=ab−ac+ac−bc=b(a−c)=VP
b, VT=a(b−c)−b(a+c)=ab−ac−ab−bc=−c(a+b)=VPVT=a(b−c)−b(a+c)=ab−ac−ab−bc=−c(a+b)=VP
c, VT=a(b+c)−b(a−c)=ab+ac−ab+bc=c(a+b)=VPVT=a(b+c)−b(a−c)=ab+ac−ab+bc=c(a+b)=VP
d, VT=a(b−c)−a(b+d)=ab−ac−ab−ad=−a(c+d)=VPVT=a(b−c)−a(b+d)=ab−ac−ab−ad=−a(c+d)=VP
e,VT=(a+b)(c+d)−(a+d)(b+c)=ac+ad+bc+bd−ab−ac−db−dc=ad+bc−ab−dc=a(d−b)−c(d−b)=(a−c)(d−b)=VPVT=(a+b)(c+d)−(a+d)(b+c)=ac+ad+bc+bd−ab−ac−db−dc=ad+bc−ab−dc=a(d−b)−c(d−b)=(a−c)(d−b)=VP