How do you simplify 5−[(−3i+4)−2i]?

1 Answer
Shwetank Mauria
Jun 23, 2016

5−[(−3i+4)−2i]=1+5i

Explanation:

5−[(−3i+4)−2i]

= 5−[−3i+4−2i]

= 5−[−5i+4]

Now we have a negative sign outside brackets.

How do we interpret it?

There are two ways

(i) it is as if we are multiplying by −1 and hence

−[−5i+4]=−1×[−5i+4]

= (−1)×(−5i)+(−1)×4=5i−4 or

(ii) using simple properties of negative numbers i.e. negative of a negative is positive and negative of a positive is negative and hence again −{−5i+4]=5i−4.

In any case, it means we change all the signs inside the brackets and above is equal to

5+5i−4

= 1+5i

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