Which expression is equivalent to the given expression?

[tex]\[ 3x^2 + 5x - 7(x^2 + 4) \][/tex]

A. [tex]\[ x^2 + 28 \][/tex]

B. [tex]\[ -4x^2 + 5x - 28 \][/tex]

C. [tex]\[ -4x^2 + 5x - 4 \][/tex]

D. [tex]\[ x^2 + 4 \][/tex]



Answer :

To determine which expression is equivalent to the given expression [tex]\(3x^2 + 5x - 7(x^2 + 4)\)[/tex], we can follow these steps to simplify it:

1. Distribute the [tex]\(-7\)[/tex] within the parentheses:
[tex]\[ -7(x^2 + 4) = -7x^2 - 28 \][/tex]

2. Rewrite the original expression with the distribution applied:
[tex]\[ 3x^2 + 5x - 7x^2 - 28 \][/tex]

3. Combine like terms:
- First, combine the [tex]\(x^2\)[/tex] terms:
[tex]\[ 3x^2 - 7x^2 = -4x^2 \][/tex]
- Then, combine the constants and the [tex]\(x\)[/tex] term:
[tex]\[ -4x^2 + 5x - 28 \][/tex]

So, the simplified form of the expression [tex]\(3x^2 + 5x - 7(x^2 + 4)\)[/tex] is:

[tex]\[ -4x^2 + 5x - 28 \][/tex]

Now, let's compare this simplified expression with the given options:

A. [tex]\(x^2 + 28\)[/tex] \\
B. [tex]\(-4x^2 + 5x - 28\)[/tex] \\
C. [tex]\(-4x^2 + 5x - 4\)[/tex] \\
D. [tex]\(x^2 + 4\)[/tex]

We see that our simplified expression [tex]\(-4x^2 + 5x - 28\)[/tex] matches option B exactly.

Therefore, the expression that is equivalent to [tex]\(3x^2 + 5x - 7(x^2 + 4)\)[/tex] is option B: [tex]\(-4x^2 + 5x - 28\)[/tex].