Question

Stiind ca 3a+5b= 5,7 si a+c=1,3 calculati:
A) 4a+5b
B) 5a+5b+2c

Answer 1

3a+5b=5,7          a+c=1,3
a)
4a+5b=?
3a+5b+a+c=5,7+1,3
4a+5b+c=7
4a+5b=7-c
b)
5a+5b+2c=?
3a+5b+a+c+a+c=5,7+1,3+1,3=
5a+5b+2c=8,3