Question

If a+b=12 and a-b=8 then what is the value of 2a+4b=?

Answer 1

a+b=12-->1
a-b=8--->2
operating 1 - 2
2b=4
b=4/2
b=2
Use b in 1
a+2=12
a=10

2(10)+4(2)
20+8
=28

Answer 2

Answer:

a + b = 12

or b= 12 -a                   (i)

by putting first equation in a - b =8

then a - b =8

or a - (12 - a) =8

or 2a - 12 = 8

or a = 10

then b = 2

2a + 4b = 2(10) + 4(2) = 20 + 8 = 28

Step-by-step explanation: