Question

X - Y = 1
X + Y = 9

X - Y = 16
X + Y = 74

Answer 1

X= 5 Y=4

X= 45 Y= 29

Resolução

2x= 10

x= 10/2

x=5

5-y = 1

y= 5-1

y=4

2x=90

x=90/2

x= 45

45-y=16

y= 45-16

y= 29