2007-11-13 06:50:39 · 30 answers · asked by sara c 1 in Science & Mathematics ➔ Mathematics
(a + bi)(a - bi)
= a^2 +a(bi) - a(bi) - bi^2
= a^2 - b^2(-1)
= a^2 + b^2 ANSWER
2007-11-13 06:55:16 · answer #1 · answered by Anonymous · 1⤊ 0⤋
To multiply polynomials, use the FOIL method. Multiply the first, then the outer, then the inner, then the last.
For example: (x+5)(x-3) would be simplified as such:
First: x*x = x^2
Outer: x*-3 = -3x
Inner: 5*x = 5x
Last: 5*-3 = -15
Add all those together and you get: x^2 +2x -15.
Boom.
2007-11-13 06:55:18 · answer #2 · answered by K A 1 · 0⤊ 0⤋
(a+bi)(a-bi)
>use the FOIL method like you would any real-number equation
a² -abi + abi -(bi)²
here, -abi and +abi cancel out, leaving you with:
a² -(bi)²
now break down -(bi)²
-(b²×i²)
we know that i² is -1
so that simplifies to +b²
your final answer is
a²+b²
2007-11-13 06:58:56 · answer #3 · answered by Ashley M 3 · 1⤊ 0⤋
(a+bi)(a-bi)
=(a)^2 - (bi)^2
= a^2 - (b^2)(i^2)
= a^2 - (b^2)(-1)
= a^2 + b^2
2007-11-13 06:55:52 · answer #4 · answered by Anonymous · 1⤊ 0⤋
i^2 = -1
(a+bi)(a-bi) =
a^2 + abi - abi - (bi)^2 =
a^2 - (b^2)(i^2) =
a^2 - (b^2)(-1) =
a^2 + b^2
2007-11-13 06:54:58 · answer #5 · answered by Raymond 7 · 1⤊ 0⤋
a^2 - bi^2
2007-11-13 07:00:25 · answer #6 · answered by Starry 4 · 0⤊ 1⤋
= a*a + a*-bi + bi*a +bi*-bi
= a^2 -abi + abi - bi^2
= a^2 - bi^2
2007-11-16 22:54:12 · answer #7 · answered by Rayan Ghazi Ahmed 4 · 0⤊ 0⤋
Foil it first and get:
a^2 -abi+abi-bi^2
The plus and minus abi's cancel out and your left with:
a^2-bi^2
2007-11-13 06:55:20 · answer #8 · answered by PrincessJ 3 · 0⤊ 1⤋
(a+ bi) (a- bi)= (a^2)- ((b^2)*(i)^2)
i^2= -1 assuming by i you mean the standard notation sqrt(-1)
therefore
= a^2- (-1*b^2)
ans= a^2+b^2
2007-11-13 06:57:30 · answer #9 · answered by Anonymous · 1⤊ 0⤋
is it a to the power of 2
2007-11-13 06:54:31 · answer #10 · answered by Peran S 1 · 0⤊ 1⤋