Respuesta :
A complex number is a part of a number system that includes a real unit and an imaginary unit. All the statements are true except C and E.
What is a Complex Number?
A complex number is a part of a number system that includes the real numbers as well as a particular element labelled i, sometimes known as the imaginary unit, and which obeys the equation i² = 1.
As it is given that x=(a+bi), y=(c+di), and z=(f+gi), therefore, we need to plug in the values to check which all are true.
A.) x+y=y+x
[tex]x+y=y+x\\a+bi+c+di=c+di+a+bi[/tex]
As the two sides of the equation are equal, the equation is true.
B.) (x × y) × z = x × (y × z)
[tex](x \times y) \times z = x \times (y \times z)\\\\\ [ (a+bi) \times (c+di) ]\times (f+gi) = (a+bi) \times [(c+di) \times (f+gi)]\\\\(ac+adi+bci-bd) \times (f+gi)= (a+bi) \times (cf+cgi+fdi-dg)[/tex]
[tex](ac+adi+bci-bd) \times (f+gi)= (a+bi) \times (cf+cgi+fdi-dg)\\\\\\acf+adfi+bcfi-bdf+acgi-adg-bcg-bdgi = acf+acgi+afdi-adg + bcfi-bcg-bfd-bdgi[/tex]
As the two sides of the equation are equal, the equation is true.
C.) x−y=y−x
[tex]x-y=y-x\\\\(a+bi)-(c+di)=(c+di)-(a+bi)\\\\a+bi-c-di=c+di-a-bi[/tex]
As the two sides of the equation are not equal, the equation is not true.
D.) (x+y)+z=x+(y+z)
[tex](x+y)+z=x+(y+z)\\\\(a+bi+c+di)+f+gi = a+bi+(c+di+f+gi)\\\\a+bi+c+di+f+gi = a+bi+c+di+f+gi[/tex]
As the two sides of the equation are equal, the equation is true.
E.) (x−y)−z=x−(y−z)
[tex](x-y)-z=x-(y-z)\\\\(a+bi-c-di)-f-gi = a+bi-(c+di-f-gi)\\\\a+bi-c-di-f-gi =a+bi-c-di+f+gi)[/tex]
As the two sides of the equation are not equal, the equation is not true.
Hence, all the statements are true except C and E.
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