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Select the correct answer.

Which expression is equivalent to the given expression?

[tex]\[ -2x^2 + 8x - 9 + 4x + 7x^2 + 2 \][/tex]

A. [tex]\(-5x^2 + 4x + 11\)[/tex]

B. [tex]\(-9x^2 + 4x - 7\)[/tex]

C. [tex]\(5x^2 + 12x - 7\)[/tex]

D. [tex]\(-9x^2 - 12x + 11\)[/tex]


Sagot :

To simplify the given expression and find the equivalent expression among the given choices, follow these steps:

Given expression:
[tex]\[ -2 x^2 + 8 x - 9 + 4 x + 7 x^2 + 2 \][/tex]

1. Combine like terms:

- First, combine all the [tex]\(x^2\)[/tex] terms:
[tex]\[ -2x^2 + 7x^2 = (7 - 2)x^2 = 5x^2 \][/tex]

- Next, combine all the [tex]\(x\)[/tex] terms:
[tex]\[ 8x + 4x = (8 + 4)x = 12x \][/tex]

- Finally, combine the constant terms:
[tex]\[ -9 + 2 = -7 \][/tex]

2. Summarize the simplified expression:
[tex]\[ 5x^2 + 12x - 7 \][/tex]

Now, let's examine the choices provided and see which one matches our simplified expression:

A. [tex]\(-5x^2 + 4x + 11\)[/tex] — this does not match.
B. [tex]\(-9x^2 + 4x - 7\)[/tex] — this does not match.
C. [tex]\(5x^2 + 12x - 7\)[/tex] — this is exactly what we obtained.
D. [tex]\(-9x^2 - 12x + 11\)[/tex] — this does not match.

Thus, the correct answer is:

[tex]\[ \boxed{C} \][/tex]