Question

a+a+a=30
a+b+b=20
b+2c+2c=9
b+c*a =

Answer 1

Refer to the attachment please

Answer 2

Answer:

3a=30

a=10 a+2b=20 2b=10 b=5 b+4c=9 4c=4 c=1 b+c×a=5+1×10=15