Answer:
15
General Formulas and Concepts:
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
Equality Properties
- Multiplication Property of Equality
- Division Property of Equality
- Addition Property of Equality
- Subtraction Property of Equality<u>
</u>
Step-by-step explanation:
<u>Step 1: Define</u>
<em>Identify</em>
5a - 10b = 45
<em>b</em> = 3
<u>Step 2: Solve for </u><em><u>a</u></em>
- Substitute in <em>b</em> [Equation]: 5a - 10(3) = 45
- Multiply: 5a - 30 = 45
- [Addition Property of Equality] Add 30 on both sides: 5a = 75
- [Division Property of Equality] Divide 5 on both sides: a = 15
You want log √(9/25). Recognizing that √9 = 3 and that √25 = 5, we get
log 3/5, which by rules of logs comes out to log 3 - log 5.
To four decimal places:
log 3 - log 5 = 0.4771 - 0.6990, or -0.2218.
A. Stiles. For Melendez, each family member uses about 390 kilowatts of electricity. For Barton, each family member uses about 355 kilowatts of energy. Stiles uses 745 kilowatts per family member. 745 divided by 355 rounds up to 2 while 745 divided by 390 rounds up to 2. This means that the Stiles family uses twice the amount of electricity per person than the other families.
b. The Melendez family. The Melendez family uses 875 gallons per family member. The Barton family uses about 1067 gallons of water while the Stiles family uses about 1250 gallons. 875< 1067< 1250. This means that the Melendez family uses the least amount of water per family member.