Răspuns: y=400
Explicație pas cu pas:
19×25+2×[9×5+2×(y-149×2)]=973
475+2×[45+2×(y-298)]=973
2×[45+2×(y-298)]=973-475
2×[45+2×(y-298)]=498
45+2×(y-298)=498÷2
45+2×(y-298)=249
2×(y-298)=249-45
2×(y-298)=204
y-298=204÷2
y-298=102
y=102+298
y=400
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Verificare:
19×25+2×[9×5+2×(400-149×2)]=973
475+2×[45+2×(400-298)]=973
475+2×(45+2×102)=973
475+2×(45+204)=973
475+2×249=973
475+498=973
