Rewrite this symbolically: 6(2/6) = 12/6 = 2 (answer)
An equally good approach would be to cancel the 6's, obtaining 2 (answer)
Answer:
9
Step-by-step explanation:
nine is the highest number in each of them
There are two ways to work this out: normal variables or using "imaginary" numbers.
Normal variables:
![(7+2i)(3-i)\\(7*3)+[7*(-i)]+(3*2i)+[2i*(-i)]\\21-7i+6i-2i^{2}\\\\21-i-2i^{2}](https://tex.z-dn.net/?f=%20%287%2B2i%29%283-i%29%5C%5C%287%2A3%29%2B%5B7%2A%28-i%29%5D%2B%283%2A2i%29%2B%5B2i%2A%28-i%29%5D%5C%5C21-7i%2B6i-2i%5E%7B2%7D%5C%5C%5C%5C21-i-2i%5E%7B2%7D)
Imaginary numbers:
Using the result from earlier:
Now since
, then the expression becomes:
Answer:
50 minutes
Step-by-step explanation:
she spent 1 hr and 30 minutes on homework
she spends 2/3 of an hour on the phone = 40 minutes
1 hr 30 min + 40 minutes = 2 hrs and 10 min
so she had 50 minutes to kill before bedtime since she goes to sleep 3 hrs after dinner
2hr 10 min + 50 min = 3 hrs.
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.
