Question

Se stie ca a+b = 45 si ac+bc =450,sa se calculeze:
a) a+b-c
b)a+b+2c
c)3a+3b+4c

Answer 1

a+b = 45
ac+bc =450⇒c(a+b)=450⇒c·45=450⇒c=450:45⇒c=10


a)( a+b)-c=45-10=35
b)(a+b)+2c=45+2·10=45+20=65
c)3a+3b+4c=3(a+b)+4c=3·45+4·10=135+40=175