Question

X+y=19 , -x+y=1 (subtraction)

Answer 1

x + y = 19
-x + y = 1
2y = 20
2 2
y = 10
x + y = 19
x + 10 = 19
- 10 - 10
x = 9
(x, y) = (9, 10)

Answer 2

ok so elimination
add them togehter
x+y=19
-x+y=1 +
0x+2y=20

2y=20
divide both sides by 2

y=10
subsitute
x+y=19
x+10=19
subtrac 10
x=9

x=9
y=10
(x,y)
(9,10)