Question

números que al sumaren den 100 y al restarse 70

Answer 1

x+y= 100
x-y=70
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*x=100-y

100-y-y=70
-2y=70-100
-2y=-30
-y= -30/2
-y = - 15
y= 15

x+15=100
x = 100-15
x = 85

15 y 85