Answer:
(x, y) = (6, 2)
Step-by-step explanation:
You solve for x and y by writing equations that reflect the relation applicable to the given geometry.
The diagonals of a parallelogram bisect each other. That means the halves of each diagonal are equal.
2x -4 = 4y . . . . . . down diagonal
x +4 = 7y -4 . . . . . up diagonal
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We can subtract the first equation from 2 times the second equation to eliminate the x-variable.
2(x +4) -(2x -4) = 2(7y -4) -(4y)
2x +8 -2x +4 = 14y -8 -4y . . . . . . eliminate parentheses
12 = 10y -8 . . . . . . . . . . . . . . . . . collect terms
20 = 10y . . . . . . . . . . . . . . . . . . add 8
2 = y . . . . . . . . . . . . . . . . . . . . divide by 10
Substituting into the second equation gives ...
x +4 = 7(2) -4
x = 6 . . . . . . . . . . . . subtract 4
The values of x and y are (x, y) = (6, 2).
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The lengths of the diagonals are 20 and 16.
