Question

Evaluate the following expression, when x=-2

2x^2+4x-3

A) 3
B) 3
C) -19
D) 9

Answer 1

A) -3

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

Explanation:

Step 1: Define

2x² + 4x - 3

x = -2

Step 2: Evaluate

1. Substitute in x: 2(-2)² + 4(-2) - 3
2. Exponents: 2(4) + 4(-2) - 3
3. Multiply: 8 - 8 - 3
4. Subtract: -3

Answer 2

`\huge\boxed{\text{A) -3}}`

Explanation:

To find the value of this equation when
`x=-2`, we can substitute this value inside the equation and use PEMDAS to successfully find the value.

With the expression of
`2x^2+4x-3`, let's substitute -2 in as x.

• 
  `2(-2)^2 + 4(-2) - 3`

Now let's follow PEMDAS to solve this equation.

PEMDAS states that when solving an expression/equation, the order we must follow is

• Parentheses
• Exponents
• Multiplication/
• Division
• Addition/
• Subtraction

We can now solve for this.

We see that exponents come before multiply and dividing. Therefore:

• 
  `2(-2)^2 = 2 \cdot (-2)^2 = 2 \cdot 4 = 8`

So the value of our first term is 8.

Our second term will be
`4 \cdot -2 = -8`, and our last term will remain -3.

Adding these values together:

`8 - 8 - 3 = -3`

Therefore, the value of this expression when x = -2 is -3.

Hope this helped!