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aflati suma a patru nr intregi consecutive , stiind ca unul dintre ele este : a) -2 b) -5;c)1

Răspuns :

a)-2, -1, 0, 1. Suma este -2.
b)-5, -4, -3, -2. Suma este -14.
c)1, 2, 3, 4. Suma este 10.
[tex]a,b,c,d-nr.[/tex]

[tex]a)1)pt. \: a = - 2[/tex]

[tex] = > b = a + 1 = - 2 + 1 = - 1[/tex]

[tex] = > c = b + 1 = - 1 + 1 = 0[/tex]

[tex] = > d = c + 1 = 0+ 1 = 1[/tex]

[tex]a + b + c + d = - 2 - 1 + 0 + 1 = - 2[/tex]

[tex]2)pt. \: b = - 2[/tex]

[tex] = > a = b - 1 = - 2 - 1 = - 3[/tex]

[tex] = > c = b + 1 = - 2 + 1 = - 1[/tex]

[tex] = > d = c + 1 = - 1 + 1 = 0[/tex]

[tex]a + b + c + d = - 3 - 2 - 1 + 0 = - 6[/tex]

[tex]3)pt. \: c = - 2[/tex]

[tex] = > a = c - 2 = - 2 - 2 = - 4[/tex]

[tex] => b = a + 1 = - 4 + 1 = - 3[/tex]

[tex] = > d = c + 1 = - 2 + 1 = - 1[/tex]

[tex]a + b + c + d = - 4 - 3 - 2 - 1 = - 10[/tex]

[tex]4)pt. \: d = - 2[/tex]

[tex] = > a = d - 3 = - 2 - 3 = - 5[/tex]

[tex] = > b = a + 1 = - 5 + 1 = - 4[/tex]

[tex] = > c = b + 1 = - 4 + 1 = - 3[/tex]

[tex]a + b + c + d = - 5 - 4 - 3 - 2 = - 14[/tex]

[tex]b)1)pt. \: a = - 5[/tex]

[tex] = > b = a + 1 = - 5 + 1 = - 4[/tex]

[tex] = > c = b + 1 = - 4 + 1 = - 3[/tex]

[tex] = > d = c + 1 = - 3 + 1 = - 2[/tex]

[tex]a + b + c + d = - 5 - 4 - 3 - 2 = - 14[/tex]

[tex]2)pt. \: b = - 5[/tex]

[tex] = > a = b - 1 = - 5 - 1 = - 6[/tex]

[tex] = > c = b + 1 = - 5 + 1 = - 4[/tex]

[tex] = > d = c + 1 = - 4 + 1 = - 3[/tex]

[tex]a + b + c + d = - 6 - 5 - 4 - 3 = - 18[/tex]

[tex]3)pt. \: c = - 5[/tex]

[tex] = > a = c - 2 = - 5 - 2 = - 7[/tex]

[tex] = > b = a + 1 = - 7 + 1 = - 6[/tex]

[tex] = > d = c + 1 = - 5 + 1 = - 4[/tex]

[tex]a + b + c + d = - 7 - 6 - 5 - 4 = - 22[/tex]

[tex]4)pt. \: d = - 5[/tex]

[tex] = > a = d - 3 = - 5 - 3 = - 8[/tex]

[tex] = > b = a + 1 = - 8 + 1 = - 7[/tex]

[tex] = > c = b + 1 = - 7 + 1 = - 6[/tex]

[tex]a + b + c + d = - 8 - 7 - 6 - 5 = - 26[/tex]

[tex]c)1)pt. \: a = 1[/tex]

[tex] = > b = a + 1 = 1 + 1 = 2[/tex]

[tex] = > c = b + 1 = 2 + 1 = 3[/tex]

[tex] = > d = c + 1 = 3 + 1 = 4[/tex]

[tex]a + b + c + d = 1 + 2 + 3 + 4 = 10[/tex]

[tex]2)pt. \: b = 1[/tex]

[tex] = > a = b - 1 = 1 - 1 = 0[/tex]

[tex] = > c = b + 1 = 1 + 1 = 2[/tex]

[tex] = > d = c + 1 = 2 + 1 = 3[/tex]

[tex]a + b + c + d = 0 + 1 + 2 + 3 = 6[/tex]

[tex]3)pt. \: c = 1[/tex]

[tex] = > a = c - 2 = 1 - 2 = - 1[/tex]

[tex] = > b = a + 1 = - 1 + 1 = 0[/tex]

[tex] = > d = c + 1 = 1 + 1 = 2[/tex]

[tex]a + b + c + d = - 1 + 0 + 1 + 2 = 2[/tex]

[tex]4)pt.\:d=1[/tex]

[tex]=>a=d-3=1-3=-2[/tex]

[tex]=>b=a+1=-2+1=-1[/tex]

[tex]=>c=b+1=-1+1=0[/tex]

[tex]a+b+c+d=-2-1+0+1=-2[/tex]