Respuesta :
Answer:
[tex]\displaystyle a = 23[/tex]
General Formulas and Concepts:
Math
- Simplifying
Pre-Algebra
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
- Left to Right
Equality Properties
- Multiplication Property of Equality
- Division Property of Equality
- Addition Property of Equality
- Subtraction Property of Equality
Step-by-step explanation:
Step 1: Define
[tex]\displaystyle \frac{2}{10} = \frac{4}{a - 3}[/tex]
Step 2: Solve for a
- [Proportion] Simplify fraction: [tex]\displaystyle \frac{1}{5} = \frac{4}{a - 3}[/tex]
- [Multiplication Property of Equality] Cross-multiply: [tex]\displaystyle a - 3 = 20[/tex]
- [Addition Property of Equality] Add 3 on both sides: [tex]\displaystyle a = 23[/tex]
Here we see that in order for the proportion to be equal, a must equal 23. Plugging in a back into the proportion should yield us a fraction equivalent to the original fraction.
Solution:
Step-1: Use cross multiplication
- [tex]\frac{2}{10} = \frac{4}{a - 3}[/tex]
- [tex]2(a - 3) = 4(10)[/tex]
Step-2: Simplify both sides
- [tex]2(a - 3) = 4(10)[/tex]
- [tex]2a - 6 = 40[/tex]
Step-3: Add 6 both sides
- [tex]2a - 6 + 6 = 40 + 6[/tex]
- [tex]2a = 46[/tex]
Step-4: Divide 2 both sides
- [tex]2a = 46[/tex]
- => [tex]\frac{2a}{2} = \frac{46}{2}[/tex]
- => [tex]a = 23[/tex]
Double-check:
Step-1: Substitute the value of a into the proportion
- [tex]\frac{2}{10} = \frac{4}{a - 3}[/tex]
- => [tex]\frac{2}{10} = \frac{4}{23 - 3}[/tex]
- => [tex]\frac{2}{10} = \frac{4}{20}[/tex]
Step-2: Simplify both sides.
- [tex]\frac{2}{10} = \frac{4}{20}[/tex]
- => [tex]\frac{1}{5} = \frac{1}{5} (Correct)[/tex]
The value of a must be 23 to make the proportion true.