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Determine which expressions represent purely real numbers and which expressions represent non-real complex numbers. [tex]7 - 5i[/tex][tex] - i {}^{2} + i ^{3} [/tex][tex] \sqrt{( - 5) ^{2} }[/tex][tex]i ^{6} [/tex][tex]0 + 9i[/tex][tex] \sqrt{ - 6} [/tex][tex]2 - {7i}^{2} [/tex][tex] - 12[/tex]

Sagot :

We have the next numbers and we need to classify them in purely real numbers and non-real complex numbers.

for

7-5i - it is a non-real complex number because we have an imaginary number

for

[tex]-i^2+i^3[/tex]

we need to reduce the expression above

[tex]-i^2+i^3=1-i[/tex]

as we can see the expression is a non-real complex number because we have an imaginary number.

For

[tex]\sqrt[]{(-5)^2}[/tex]

we need to simplify the expression

[tex]\sqrt[]{(-5)^2}=5[/tex]

as we can see we have purely real number

For

[tex]i^6=i^2\cdot i^2\cdot i^2=-1\cdot-1\cdot-1=-1[/tex]

as we can see we have a purely real number

For

[tex]0+9i[/tex]

we have a non-real complex number

For

[tex]\sqrt[]{-6}=i\sqrt[]{6}[/tex]

if we have inside a square root a negative number the result will be a non-real complex number.

For

[tex]2-7i^2=2-7(-1)=2+7=9[/tex]

as we can see we have a purely real number

for

-12 we have a purely real number