A + b = 15 ..... eq 1
a – b = 12 ...... eq 2
So a = 15 – b
Substitute in eq 2 :
15 – b – b = 12
15 – 2b = 12
–2b = 12 – 15
b = 1.5
So a = 15 – 3/2 = 13.5
4ab = 4 x 13.5 x 1.5 = 81
Use trigonometry.
cos(18°) = x/25
Multiply both sides by 25.
cos(18°)25 = x
23.7764129074 = x
We round off to the nearest hundredth. This means to round off to two decimal places.
Doing so, we get 23,78 cm = x.
<h3>The equation represents the total amount Emma earns at the event is y = 10x</h3>
<em><u>Solution:</u></em>
Given that,
<em><u>The total amount Emma earns, y, is proportional to the number of bracelets, x, she sells</u></em>

Where,
y is the total amount Emma earns
x is the number of bracelets
k is the cost of each bracelet
<em><u>Emma earns $10 for each sold bracelet</u></em>
Therefore, k = 10
Thus, eqn 1 becomes,
<h3>y = 10x</h3>
Thus the equation represents the total amount Emma earns at the event is found
Answer:

General Formulas and Concepts:
<u>Pre-Algebra</u>
- Order of Operations: BPEMDAS
<u>Algebra I</u>
- Standard Form: ax² + bx + c = 0
- Quadratic Formula:

Step-by-step explanation:
<u>Step 1: Define equation</u>
-3x = 2x² - 4
<u>Step 2: Rewrite into Standard Form</u>
0 = 2x² + 3x - 4
<u>Step 3: Define variables</u>
a = 2
b = 3
c = -4
<u>Step 4: Find </u><em><u>x</u></em>
- Substitute:

- Evaluate:

- Multiply:

- Add:

- Evaluate:

- Evaluate:

And we have our final answer!