Răspuns :
x+4,x^2+1,2x+7 apartin a de n
X+4= a1
X^2+1=a2
2x+7=a3
a2=(a1+a3)/2 {din teorie}
X^2+1= (x+4+2x+7)/2
X^2+1=(3x+11)/2
2x^2+2=3x+11
2x^2-3x-9=0
Delta= 9+36•2
Delta= 81
Radical din delta = 9
X1= 3+9/2•2= 12/4= 3
X2=3-9/4=-6/4=-3/2
Solutie : {3; -3/2}
X+4= a1
X^2+1=a2
2x+7=a3
a2=(a1+a3)/2 {din teorie}
X^2+1= (x+4+2x+7)/2
X^2+1=(3x+11)/2
2x^2+2=3x+11
2x^2-3x-9=0
Delta= 9+36•2
Delta= 81
Radical din delta = 9
X1= 3+9/2•2= 12/4= 3
X2=3-9/4=-6/4=-3/2
Solutie : {3; -3/2}