Practice problem2





                 In this page practice problem2 we will see how to solve subtraction problems on complex numbers.

Solution:

  1. (2+3i)-(9-11i)

While subtracting two complex numbers we have to subtract the real parts together and imaginary parts together. We have to subtract the real and imaginary parts like ordinary subtraction.

The real parts of the given numbers are 2 and 9.

The imaginary parts of the given numbers are 3i and -11i.

[Here we have to subtract -11i from 3i.  Writing this with subtracting symbol we will get 3i-(-11i). So the underlined part will become as 11i as negative multiplied by negative sign is positive sign.]

Let us subtract these now.

                 = (2-9) + (3i-(-11i))

                 =   (-7)  +  (3i+11i)

                 =     -7   +14i

         2.  (4-5i)-(3+4i)

The real parts of the given numbers are 4 and 3.

The imaginary parts of the given numbers are -5i and 4i.

Let us subtract these numbers now.

                 = (4-3) + (-5i-4i)

                 =     1   +  (-9i)

                 =     1   -  9i

          3.  (-8+9i)-(-7+5i)

The real parts of the given numbers are -8 and -7.

The imaginary parts of the given numbers are 9i and 5i.

Let us subtract these numbers now.

                 =  (-8-(-7)) + (9i-5i)

                 =    (-8+7)   +     4i

                 =        -1    +  4i

           4.   (-8-9i)-(-11-13i)

The real parts of the given numbers are -8 and -11.

The imaginary parts of the given numbers are -9i and -13i.

Let us subtract these numbers now.

                 = ((-8)-(-11)) + ((-9i)-(-13i))

                 =    (-8 +11)   +     (-9i+13i)

                 =         3   +  4i

        Parents and teachers can guide the students to practice the problems discussed in practice problem2 and ask them to solve the problems given below.

Problems for practice:

  1. (23-8i)-(-7-2i)
  2. (4+9i)-(2-5i)

        If you have any doubts you can contact us by mail, we will clear all your doubts.

      





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