If x + 3y = 8 and 4x – 7y = 1, what is the value of x + y?

We have the two equations x + 3y = 8 and 4x – 7y = 1. We
can see that it is not possible to multiply the equations by any number and add or
subtract them to achieve a common coefficient for x and y that can be canceled to yield
the value of x+y.

So, let’s find x and y and use that to
determine their sum.

We have x + 3y =
8

=> x = 8 –
3y

substitute this in 4x – 7y =
1

=> 4(8 – 3y) – 7y =
1

=> 32 – 12y – 7y =
1

=> -19y =
-31

=> y = 31/19

x = 8
– 3*(31/19)

=> x =
59/19

The sum x + y = 31/19 + 59/19 =
90/19