Răspuns:
6)a) a=3√2+6√3
b= 5√2-3√3
c=-8√2-3√3
a+b+c=(3√2+6√3)+(5√2-3√3)+(-8√2-3√3)=3√2+6√3+5√2-3√3-8√2-3√3
a+b+c=3√2+5√2-8√2+6√3-3√3-3√3=0∈Z
b) a= 3-2√7
b=3√7+1
c=-√7-1
a+b+c=(3-2√7)+(3√7+1)+(-√7-1)=3-2√7+3√7+1-√7-1=-2√7+3√7-√7+3+1-1=√7-√7+3=0+3=3∈Z
c) a= -2√6+5√2
b=9√2-4√6
c=6√6-14√2
a+b+c=(-2√6+5√2)+(9√2-4√6)+(6√6-14√2)=-2√6+5√2+9√2-4√6+6√6-14√2=-2√6-4√6+6√6+9√2+5√2-14√2= -6√6+6√6+14√2-14√2=0∈Z
d) a=12-√7
b=3√7+3
c= -2√7+1
a+b+c=(12-√7)+(3√7+3)+(-2√7+1)=12-√7+3√7+3-2√7+1=-√7+3√7-2√7+12+3+1=2√7-2√7+16=0+16=16∈Z
7) a) 2√3+5√3-(7√3+2√3)=7√3-9√3= -2√3
b)11√7+7√7-(3√7-5√7)=18√7-(-2√7)=18√7+2√7=20√7
c) 2√5-4√5+(2√5+9√5-7√5)= -2√5+4√5=2√5
d) √5+(-3√5+6√5)-(-3√5-9√5)=√5+3√5-(-12√5)=4√5+12√5=16√5
e)2√6+3√3-(5√6-3√3)+(-3√6-9√3)=2√6+3√3-5√6+3√3-3√6-9√3=2√6-5√6-3√6+3√3+3√3-9√3=-6√6-3√3
f)(-9√13+5√13)-(8√13-√13)+7√11=-4√13-7√13+7√11=-11√13+7√11
g)(3√2-2√3)+(-4√2-3√3)-(6√2-5√3)=3√2-2√3-4√2-3√3-6√2+5√3=3√2-4√2-6√2-2√3-3√3+5√3=-7√2-5√3+5√3=-7√2
Explicație pas cu pas:
