Afarm is to be built in the shape of quadrilateral abcd, as shown below. all four sides are equal. what is the area of the farm? 62 square feet 52.8 square feet 57.4 square feet 102.3 square feet

the answer is 102.3 and this is correct!

  b: elimination

Step-by-step explanation:

My vote is for elimination, though any of these methods (and some not listed) will get an answer quickly.

Subtracting the second equation from twice the first gives ...

  2(9x +8y) -(18x -15y) = 2(7) -(14)

  31y = 0 . . . simplify

  y = 0 . . . . . divide by 31 (or invoke the zero-product rule)

Then the value of x can be found from the first equation:

  9x = 7

  x = 7/9

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I like this method because it tells you that y=0 in one step. (Graphing does the same.) For the numbers here, you can do it mentally. Once you recognize that the x-coefficients and the constants are related by the same factor, and that factor is different for the y-coefficients, it becomes apparent that elimination will immediately tell you that y=0.