The correct option as per me is (b)
Answer:

General Formulas and Concepts:
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
Equality Properties
Step-by-step explanation:
<u>Step 1: Define</u>
<u />
<u />
<u />
<u>Step 2: Solve for </u><em><u>x</u></em>
- Cross-multiply:

- Distribute:

- Isolate <em>x</em> terms:

- Isolate <em>x</em> term:

- Isolate <em>x</em>:

- Rewrite:

Answer:
b
Step-by-step explanation:
∠ BAD = 90° and
∠ DAC + ∠ CAB = ∠ BAD, that is
x + 2x - 30 = 90
3x - 30 = 90 ( add 30 to both sides )
3x = 120 ( divide both sides by 3 )
x = 40 → b
In the 5/4 = ?/12 .. you have to solve if 4 goes into 12 that is 3. 4•3 equals 12. Now you have to multiply 5•3 and it will fill in your blank space. I hope this Helps.