in parallelogram abcd, be=10x-3 and de=8x-1.

what is bd?

question options:

7 units

14 units

21 units

  14 units

Step-by-step explanation:

The two halves of the diagonal are congruent, so ...

  BE = DE

  10x -3 = 8x -1

  2x = 2 . . . . . . . add 3-8x

  x = 1

BD = BE +DE = (10x -3) +(8x -1) = 18x -4

BD = 18·1 -4 = 14 . . . units

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It might be easier to figure DE = 8·1-1 = 7, then multiply by 2 to find BD = 14.

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