Select the correct answer.

Which pair of expressions are equivalent?

A. [tex]2y - 4[/tex] and [tex]2y - 4 + 9[/tex]

B. [tex]14x - 7[/tex] and [tex]7x - 14[/tex]

C. [tex]9y + 3 + 2[/tex] and [tex]3(y + 1) + 2[/tex]

D. [tex]x + y[/tex] and [tex]x - y + 2y[/tex]

E. [tex]x + 2y[/tex] and [tex]x - y[/tex]



Answer :

To determine which pair of expressions are equivalent, we need to simplify both expressions within each pair and then compare them. Let's analyze each option:

Option A:
Expressions: [tex]\(2y - 4\)[/tex] and [tex]\(2y - 4 + 9\)[/tex]

Simplifying the second expression:
[tex]\[ 2y - 4 + 9 = 2y + 5 \][/tex]

Comparing with the first expression:
[tex]\[ 2y - 4 \neq 2y + 5 \][/tex]

Therefore, [tex]\(2y - 4\)[/tex] and [tex]\(2y - 4 + 9\)[/tex] are not equivalent.

Option B:
Expressions: [tex]\(14x - 7\)[/tex] and [tex]\(7x - 14\)[/tex]

These are already simplified, but let’s compare them directly:
[tex]\[ 14x - 7 \neq 7x - 14 \][/tex]

Therefore, [tex]\(14x - 7\)[/tex] and [tex]\(7x - 14\)[/tex] are not equivalent.

Option C:
Expressions: [tex]\(9y + 3 + 2\)[/tex] and [tex]\(3(y + 1) + 2\)[/tex]

Simplifying both expressions:
[tex]\[ 9y + 3 + 2 = 9y + 5 \][/tex]
[tex]\[ 3(y + 1) + 2 = 3y + 3 + 2 = 3y + 5 \][/tex]

Comparing them:
[tex]\[ 9y + 5 = 3y + 5 \][/tex]

Therefore, [tex]\(9y + 3 + 2\)[/tex] and [tex]\(3(y + 1) + 2\)[/tex] are equivalent.

Option D:
Expressions: [tex]\(x + y\)[/tex] and [tex]\(x - y + 2y\)[/tex]

Simplifying the second expression:
[tex]\[ x - y + 2y = x + y \][/tex]

Comparing them:
[tex]\[ x + y = x + y \][/tex]

Therefore, [tex]\(x + y\)[/tex] and [tex]\(x - y + 2y\)[/tex] are equivalent.

Option E:
Expressions: [tex]\(x + 2y\)[/tex] and [tex]\(x - y\)[/tex]

These are already simplified, so let’s compare them directly:
[tex]\[ x + 2y \neq x - y \][/tex]

Therefore, [tex]\(x + 2y\)[/tex] and [tex]\(x - y\)[/tex] are not equivalent.

Conclusion:
After examining all the options, the equivalent pairs of expressions are found in Option C and Option D. Therefore, the correct answer includes the pairs provided in these options:

Answer: C and D