(-5-2i)^2
simplify . write answer in the form a+bi
need some help here thanks
2007-07-22 12:08:46 · 5 answers · asked by jesis332 1 in Science & Mathematics ➔ Mathematics
It is 25+4i^2+20i since (i^2= -1)
= 25-4+20i
=21+20i
hope i helped you...
2007-07-22 12:16:05 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Do it like FOIL: (-5 - 2i)(-5 - 2i) =
25 + 10i + 10i + 4i^2
i^2 is -1 so 4i^2 is -4
Combine like terms: 25 + -4 = 21
10i+10i=20i
So 21 + 20i
2007-07-22 19:14:02 · answer #2 · answered by hayharbr 7 · 0⤊ 0⤋
So it's (-5-2i) x (-5-2i) .... just FOIL it.
-5 x -5 = 25
-5 x -2i = 10i
-2i x -5 = 10i
-2i x -2i = -4 (since it would be 4i^2 and i^2 = -1)
So it's 21 + 20i
2007-07-22 19:13:12 · answer #3 · answered by Mitchell . 5 · 0⤊ 0⤋
(-5-2i)^2
= (-5)^2 +2(-5)(-2i) + (-2i)^2
= 25 + 20i - 4
= 21 + 20i
2007-07-22 19:12:56 · answer #4 · answered by gudspeling 7 · 0⤊ 0⤋
= 25+20i-4
=21+20i
2007-07-22 19:14:29 · answer #5 · answered by 037 G 6 · 0⤊ 0⤋