Răspuns :
a=3
b+c+d=30
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3a+2(ab+ac+ad)=3a+2[a(b+c+d)]=3×3+2(3×30)=9+2×90=9+180=189
[tex]3a + 2(ab + ac + ad) = 9 + 2a(b + c + d) = 9 + 6 \times 30 = 9 + 180 = 189[/tex]
a=3
b+c+d=30
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3a+2(ab+ac+ad)=3a+2[a(b+c+d)]=3×3+2(3×30)=9+2×90=9+180=189