Question

plsss URGENT DAU TEST ORICE RASPUNS AJUTA​

Answer 1

Răspuns:

Explicație pas cu pas:

1

z=8+6i

a)(8+6)²=14²=196

b)opusul lui z=-8+6i

conjugatul lui z=8+6i

c)IzI=√R²+I²=√64+36=√100=10

2

z1=1-3i     z2=2+i

a)z1+3z2=1-3i+6+3i=7

b)z1·z2=(1-3i)(2+i)=2-6i+i+3=5-5i

c)z1/z2=a+bi  

(1-3i)/(2+i)=(1-3i)·(2-i)/(4+1)=(2-6i-i+3)/5=(5-7i)/5

⇒a=1   b=-7/2

3

2z+zbarat=9+2i

2(a+bi)+a-bi=9+2i

2a+2bi+a-bi=9+2i

3a+bi=9+2i          ⇒a=3  si b=1

b)x²-2x+5=0

x1,2=1±√1-5=1±2i      x1=1+2i      x2=1-2i

c)x1=3-i   x2=3+i

x1+x2=6       x1x2=9+1=10

x²-6x+10=0