help please?

1.
(7+i)(7-i) = 49-i^2 = 49 - (-1) = 50

2.
The conjugate of -9+5i is -9-5i

PROBLEM 1:

You need to know how to get the conjugate. Basically all you do is change the sign in front of the imaginary term (the one with the i).

So the complex conjugate of 7 + i is 7 - i.

Now multiply those together:
(7 + i)(7 - i)

You should immediately recognize that as something that equates to a difference of squares --> (a + b)(a - b) = a² - b²

But even if you don't, you can multiply it out and cancel the middle terms to get to the same place.
(7 + i)(7 - i)
= 7² - 7i + 7i - i²
= 49 - i²

Remember the definition of the imaginary unit is i = √-1, or equivalently i² = -1:
= 49 - (-1)
= 49 + 1
= 50

Answer:
d. 50

PROBLEM 2:
As stated previously to get the conjugate, you change the sign in front of the imaginary term.
-9 + 5i
--> -9 - 5i

Answer:
b. -9 - 5i