Anonymous
Anonymous asked in Science & MathematicsMathematics · 1 decade ago

# Dividing imaginary numbers... a+bi?

4-3i / 5+5i

How do you do that?

Relevance
• 1 decade ago

4-3i / 5+5i

You need to make the denominator real, so multiply the entire thing by 5-5i/5-5i to get:

(4-3i)(5-5i)/(5+5i)(5-5i)

This foils out to:

20-20i-15i+15i^2/25-25i+25i-25i^2

This reduces to:

5-35i/50

You can reduce this to:

1-7i/25

To put it into standard form:

1/25 - 7/25i

• 1 decade ago

multiply by conjugate/conjugate of the denominator.

conjugate of a +bi is a - bi

so multiply 4-3i/5+5i by 5-5i/5-5i

the denominator will have no i terms because i^2 = -1

• mammo
Lv 4
3 years ago

rationalize 7i(-9 +14i) / 7i(7i) (-63i+ 98i^2) / 49i^2 be conscious that i^2 = -a million (-63i +ninety 8(-a million)) / 40 9(-a million) 7 (-9i -14) / -40 9 be conscious that 7 is going into 7 as quickly as and into 40 9 seven circumstances -(9i +14) / -7 9i/7 + 14/7 9i/7 + 2 2 + 9i/7

• Como
Lv 7

(4 - 3i)(5 - 5i)

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(5 + 5i)(5 - 5i)

20 - 20 i - 15 i + 15 i ²

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25 - 25 i ²

5 - 35 i

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25 + 25

5 - 35 i

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50

1 - 7 i

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10