Question

efectuati scoțând factor comun

a) (-2)×(+8)-(2)×(+5)
b) (+a)×(-2)-(-b)×(-2), a,b€ Z
c) (+13)×(-16)+(+17)×(-16)
d) (-a)×(-3)+(-a)×(+5), a€ Z


€= aparține
Z= multimea nr. intregi​

Answer 1

a) (-2)x(+8)-(2)x(+5)=

= (-2)x(+8+5)=

= (-2)x13= -36

b) (+a)x(-2)-(-b)x(-2)=

= (-2)x(+a-(-b))=

= (-2)x(a+b)

c) (+13)x(-16)+(+17)x(-16)=

= (-16)x(+13+17)=

= (-16)x 30= -480

d) (-a)x(-3)+(-a)x(+5)=

= (-a)x(-3+5)=

= (-a)x2= -2a