Răspuns:
Explicație pas cu pas:
3
(x-2)+(x+7)+2√(x-2)(x+7)=9 2x+5+2√(x-2)(x+7)=9
2√(x-2)(x+7)=-2x+4 √(x-2)(x+7)=2-x
(x-2)(x+7)=(2-x)² x+7=-x+2 2x=-5 x=-5/2
a) o solutie
test 3 ex2
log1/2=log2/log2din 1/2=-log2
2^n+1-2^2n+55=1 notan 2^n=t
t+1-2t²+55=1 2t²-t-55=0
t1,2=-1±√1+√441/2=-1±21/2 t1=-11 nu se poate t2=10
2^n=10 n=log2din10