If 3+a=4-b and 4+b=7+a, what is 3-a?

Step-by-step explanation:

3+a=4-b

4+b=7+a

a=1-b

4+b=7+1-b

2b=4

b=2

a=1-2= -1

3-a= 3- -1= 3+1=4

3-a=4

The answer is 4.

Step-by-step explanation:

First, you have to form simultaneous equations :

Next, you have to solve it :

Lastly, you have to substitute a-value into the expression :