Question

Află nr a, b, c, știind ca a+b=300, b+c=500, a+c=400

Answer 1

b=500-300=200
a=300-200=100
c=400-100=300

Answer 2

a = 300 - b
300 - b + c = 400
- b + c = 400 - 300
- b + c = 100
si
b + c = 500, adunam cu relatia de mai sus
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   /   2c = 600
c = 600 : 2
c = 300
b + 300 = 500
b = 500 - 300
b = 200
a + 200 = 300
a = 300 - 200
a = 100