How do I solve this simultaneous equation:x+y=8 x- y=1

We'll can also solve the system of simultaneous equations
using the substitution method (instead of elimination
method).

For this reason, we'll extract x from the second
equation:

x- y=1

We'll add y
both sides and we'll get:

x = y + 1
(1)

We'll substitute x into the first
equation:

x + y = 8

y + 1 + y
= 8

We'll combine like
terms:

2y + 1 = 8

2y = 8 -
1

2y = 7

y = 7/2
(2)

 We'll substitute y in
(1):

x = y + 1

x = 7/2 +
1

x = (7+2)/2

x =
9/2

The solution of the system is the pair of
coordinates (x,y):

(9/2 ,
7/2)