Answer:12
Step-by-step explanation:
it’s 12 because 4 x 3 = 12
Angle e = x angle d = 5x supplementary means they add up to 180
x + 5x =180
6x = 180
6x/6 = 180/6
x = 30
so angle e = 30 and angle d = 5(30) = 150
Add 1 to both sides:

In cases like this, we have to remember that a root is always positive, so we can square both sides only assuming that

Under this assumption, we square both sides and we have

The solutions to this equation are

But since we can only accept solutions greater than -1, we discard
and accept
.
In fact, we have

and

which is the only solution.
That's a question about percentage.
One way to represent percentage is using decimal number. In this way, 1 is equivalent to 100% and the other less percentages using numbers between 0 and 1.
Examples:
- 90% is equivalent to 0,90.
- 5% is equivalent to 0.05. It's not 0.5 because 0.5 is equivalent to 50%.
- 13.17% is equivalent to 0.1317.
- 245% is equivalent to 2.45.
If we want to know the percentage of a number, we should multiplacate the number by the porcentage in the decimal number form.
Examples:
- 55.90% of 200 is equal to:

- 360% of 88 is equal to:

In our problem, we have a phone with a increase of 7%. To solve that, it's important to perceive that $230 is equal to 100% and with a increase of 7%, we will pay 107%.
107% in the decimal number form is 1.07. With that information, we should multiplicate 1.07 by the original value and we will find the answer.
We know that
, therefore, the total cost of the phone after tax is $246.1.
I hope I've helped. :D
Enjoy your studies. \o/
Primary sources contain information
A. with the advantage of hindsight and the perspective of an outside observer and may be more objective.
B. provided by someone who's been through an event. It's a firsthand account that lends a unique perspective.
C. on statistics gathered after an important historical event.
D. on psychological information gathered from raw data from psychological tests.