Question

A rectangle with sides measuring x in. and 4x-1 in. has an area of 663in.^2. What are the dimensions of the rectangle?

Answer 1

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Answer:

  13 in by 51 in

Step-by-step explanation:

The area is the product of the dimensions, so is ...

  663 = x(4x -1)

  4x^2 -x -663 = 0 . . . . . . subtract 663 to put in standard form

Using the quadratic formula, we can find the solutions.

  x = (-(-1) ±√((-1)^2 -4(4)(-663)))/(2(4))

  x = (1 ± √10609)/8 = (1 ±103)/8

Only the positive solution is of any use in this problem, so ...

  x = 104/8 = 13

  4x-1 = 4(13)-1 = 51

The dimensions of the rectangle are 13 inches by 51 inches.

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I find it easiest to solve these using a graphing calculator.