Answer:
Dhshshshhshsjehsjsjjsjssjsjsjsjsjsjjshhdhddhhdjdjddjdjjhdhdkdhjsdfggdhjjjjd
Step-by-step explanation:
Answer:

Step-by-step explanation:
Setting it up as a fraction will help us see the simplification process a bit easier.

a/a = 1, so they cancel each other out, leaving us with simply

Answer:
Step-by-step explanation:
multiply all number on one
multiply all number on two
multiply all number on three
If you expand out the brackets you get this,
(4+5i)(a+2i) = 4a + (5a)i + 8i - 10
The -10 comes from 5i * 2i.
Squaring i becomes -1.
Let's group the real stuff together,
and imaginary separately,
(4a - 10) + (5a + 8)i
For this to be purely imaginary,
the real part needs to be zero.
Therefore 4a - 10 = 0
Solve for a.