Answer:
We need to send more than 400 messages for Plan B to be the better option.
Step-by-step explanation:
Plan A
The cost is a flat fee of 30 plus 10 cents per message
Cost= 30 +.10m
Plan B
The cost is a flat fee of 50 plus 5 cents per message
Cost = 50 +.05m
We want cost of B to be less than cost A
30 +.10m > 50 +.05m
Subtract .05m from each side
30 +.10m- .05m > 50 +.05m-.05m
30 +.05m > 50
Subtract 30 from each side
30-30 +.05m > 50-30
.05m > 20
Divide each side by .05
.05/.05m > 20/.05
m > 400
We need to send more than 400 messages for Plan B to be the better option.
First you plug in the variables:
(-3)(2)+(6)(-3)(4)
Multiply:
-6+(-18)(4)
-6+-72
Add and your answer comes out to be:
-78
The complex conjugate of a + bi is a - bi
So, the complex conjugate of -8 + 12i is -8 - 12i.
