Question

Solve using the quadratic formula. Approximate answers to the nearest tenth.

Answer 1

`\displaystyle x=-1, \ 8`

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

1. Brackets
2. Parenthesis
3. Exponents
4. Multiplication
5. Division
6. Addition
7. Subtraction

• Left to Right

Algebra I

• Standard Form: ax² + bx + c = 0
• Quadratic Formula:
  `\displaystyle x=(-b \pm √(b^2-4ac))/(2a)`

Explanation:

Step 1: Define

Identify variables

x² - 7x - 8

↓

a = 1, b = -7, c = -8

Step 2: Solve for x

1. Substitute in variables [Quadratic Formula]:
   `\displaystyle x=(7 \pm √((-7)^2-4(1)(-8)))/(2(1))`
2. [√Radical] Evaluate exponents:
   `\displaystyle x=(7 \pm √(49-4(1)(-8)))/(2(1))`
3. [√Radical] Multiply:
   `\displaystyle x=(7 \pm √(49 + 32))/(2(1))`
4. [√Radical] Add:
   `\displaystyle x=(7 \pm √(81))/(2(1))`
5. [√Radical] Evaluate:
   `\displaystyle x=(7 \pm 9)/(2(1))`
6. Multiply:
   `\displaystyle x=(7 \pm 9)/(2)`
7. Add/Subtract:
   `\displaystyle x=(-2)/(2), \ (16)/(2)`
8. Divide:
   `\displaystyle x=-1, \ 8`