Răspuns:
Explicație pas cu pas:
a + 2 x 2 = 5 x 5 - b = c x 5 = 24 : d + 9 = 15
24 : d + 9 = 15
24 : d = 15 - 9 = 6
d = 24 : 6 = 4
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c x 5 = 15
c = 15 : 5 = 3
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5 x 5 - b = 15
25 - b = 15
b = 25 - 15 = 10
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a + 2 x 2 = 15
a + 4 = 15
a = 15 - 4 = 11
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a + b = 11 + 10 = 21
c + d = 3 + 4 = 7
(a + b) : (c + d) = 21 : 7 = 3
