Evaluate the following: `2x^3+2x^2-7x+72 ,\ w h e n\ x=(3-5i)/2`

Explanation

We havegiven `x=(3-5i)/2`

then we have to find `2x^3+2x^2-7x+72`

so,

`2x^3+2x^2-7x+72=2((3-5i)/2)^3+2((3-5i)/2)^2-7((3-5i)/2)+72`

`2x^3+2x^2-7x+72=(((3-5i)(3-5i)^2)/4)+((9+25(i^2)-30i)/2)+((-21+35i)/2)+72`

since `(i^2)=-1`

`2x^3+2x^2-7x+72=(((3-5i)(9-25-30i))/4)-((16+30i)/2)+((-21+35i)/2)+72`

`2x^3+2x^2-7x+72=((3-5i)(-8-15i)-(16+30i)+(-21+35i)+144)/2`

...