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.
Answer:

Step-by-step explanation:
Equation of straight line is given as

where slope m is calculated as

<u>Here </u>


<u>Equation of line that passes through the points (1,6) and (5,2)</u>
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Answer:
6:00pm is the answer
Step-by-step explanation:
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3590 per year
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Answer:
D
Step-by-step explanation:
I'm not 100% percent sure but I believe its that one