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AB║CD and AD║BC

Step-by-step explanation:

By the property of a parallelogram,

" Consecutive angles of a parallelogram are supplementary"

In the figure attached,

∠DCB and ∠CDA are the supplementary angles. Therefore ABCD will be a parallelogram.

[Given: m(∠DCB) + m(∠CDA) = 180°]

And the pair of opposite sides of the parallelogram ABCD will be parallel.

AD║BC and AB║CD

answer:   x = 3 + √11     and     x = 3 - √11

step-by-step explanation:

x² - 6x + 9 = 11

(x - 3)² = 11

x - 3 = ±√11

    x = 3 ± √11

x = 3 + √11     and     x = 3 - √11

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step-by-step explanation:

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