Can you check my answers please

1. how do i simplify the expression (-6i)(-6i)?

i got 36i, am i right?

2. (2+5i)(-1+5i)

i got 23+5i

1. remember that i^2 = -1

so (-6i)(-6i) = 36i^2 = -36

2. (2 + 5i)(-1 + 5i) = -2 + 10i - 5i + 25i^2

= -2 - 25 + 5i = -27 + 5i

(2 + 5i)(-1 + 5i) = -27 + 5i

Remember that i^2 = -1. Use that substitution wherever you can.

1.
(-6i)(-6i)
= 36i^2
= 36 (-1)
= -36

2.
(2+5i)(-1+5i)
= -2 - 5i + 10i + 25i^2
= -2 +5i +25(-1)
= -2 + 5i - 25
= 5i - 27

(-6i)^2

Q1. No, it is 36i² = 36 x -1 = -36

Q2. (2+5i)(-1+5i)
= -2 +10i -5i + 25i²
= -2 + 5i - 25
= -27 + 5i

The first one's right, but I think the second is -2+25i ? Hope this helps;)