Find the parity of the following if a and b have different parities.
(5a - 3b)(a² + 5b) + 2

9514 1404 393

  odd

Step-by-step explanation:

If 'a' and 'b' have different parity, the result has odd parity.

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Assume a=odd, b=even

  (5·odd -3·even) = odd

  (odd^2 +5·even) = odd

  (odd)(odd) +2 = odd

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Assume a=even, b=odd

  (5·even -3·odd) = odd

  (even^2 +5(odd)) - odd

  (odd)(odd) +2 = odd

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The attached verifies this with numbers.

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

step-by-step explanation:

the true ones are a b and d