To determine which of the given responses shows that polynomials form a closed system under multiplication, we need to check if the result of multiplying two polynomials is also a polynomial.
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(√x)(6x ⋅ -3):
- Here, √x is not a polynomial (it's a radical), so the product does not guarantee that it will give a polynomial.
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(3x²/4 − 1):
- This expression is a polynomial in itself. However, it's not showing a multiplication of two separate polynomials.
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(14x³)(5) or (1/4)x³ * 5:
- 14x³ and 5 are both polynomials. Their product (14x³ * 5 = 70x³) is also a polynomial.
- Similarly, (1/4)x³ * 5 results in (5/4)x³, which is also a polynomial.
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(x)(1/2x):
- Here, both x and 1/2x are polynomials. Their multiplication results in (1/2)x², which is also a polynomial.
From these responses, the following show that polynomials form a closed system under multiplication:
- (14x³)(5) or (1/4)x³ * 5
- (x)(1/2x)
The best responses indicating closure under multiplication would be \( (14x^3)(5) \) or \( (x)(1/2x) \).