Question

Stiind ca a+b=14 si b+c=9, calculati:
a) 2a+5b+3c
b) a+8b+7c

Answer 1

Răspuns:

2a +5b+3c =

7•ab+3c=

7•14+3c= 21+3c

c=21:3

c=7

2a+5b+3c=

2a+8bc=

2a+8•9

2a+72

a=72:2

a=36

2•36 +5b+3•7

72+5b+21=

5b+72+21

5b+93

b=93:5

b=18,6

a+8b+7c