Question

Daca a = 14, iar b +c  = 25, aflati valoarea expresiilor :
a) a+b+c
b) a+3 x b+3 x c 
c) 5 x a + 2 x c + 2 x b
d) a x b + a x c + 5 x a -16 x b-16 x c

Answer 1

a = 14, iar b +c  = 25
a) a+b+c = a+(b+c)=14+25=39
b) a+3 x b+3 x c =a+3 x (b+c) = 14 + 3 x 25 = 14+75=89
c) 5 x a + 2 x c + 2 x b = 5 x a + 2 x (c+b)=5 x 14 + 2 x 25 = 70 + 50 = 120
d) a x b + a x c + 5 x a -16 x b-16 x c = a x (b+c) +5 x a -16 x (b + c )=
= a x [(b+c)+5] -16 x (b+c) = 14 x (25+5) - 16 x 25 = 14 x 30 -16 x 25 =420-400=20