There are two ways to work this out: normal variables or using "imaginary" numbers.
Normal variables:
![(7+2i)(3-i)\\(7*3)+[7*(-i)]+(3*2i)+[2i*(-i)]\\21-7i+6i-2i^{2}\\\\21-i-2i^{2}](https://tex.z-dn.net/?f=%20%287%2B2i%29%283-i%29%5C%5C%287%2A3%29%2B%5B7%2A%28-i%29%5D%2B%283%2A2i%29%2B%5B2i%2A%28-i%29%5D%5C%5C21-7i%2B6i-2i%5E%7B2%7D%5C%5C%5C%5C21-i-2i%5E%7B2%7D)
Imaginary numbers:
Using the result from earlier:

Now since

, then the expression becomes:
Answer:
0.53
Step-by-step explanation:
Make the denominators the same number. Then do the problem as you would regularly without fractions
Ok
First factor out the first 2 terms as follows:-
y = 1/2(x^2 - 8x) + 21
Now complete the square on x^2 - 8x:-
y = 1/2[ (x - 4)^2 - 16] + 21
y = 1/2(x - 4)^2 - 8 + 21
y = 1/2(x - 4)^2 + 13 Answer
Answer: 4
Step-by-step explanation:
If you convert you should get 4.