To find area you do length x width. To find perimeter you do length + width.
Answer:
x = 200
Step-by-step explanation:
Multiply by 4:
x + 120 + 2x = 720
3x = 600 . . . . . . collect terms, subtract 120
x = 200 . . . . . . . divide by 3
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<em>Check</em>
(200/4 +30) +(200/2) = 180
(50 +30) + 100 = 180
80 + 100 = 180 . . . . . true
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<em>Alternate solution</em>
If you like, you can simply work with the equation given.
(3/4)x + 30 = 180 . . . . collect terms
(3/4)x = 150 . . . . . . . . . subtract 30
x = 200 . . . . . . . . . . . . multiply by 4/3
The fact that the coefficients are pairwise identical (except for sign) tells you that x^2 -1 is a factor (and x-5 is the other factor). Of course, you recognize x^2-1 as a special form (the difference of squares) that is factored as (x +1)(x -1).
The zeros are x = -1, +1, +5.
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A graphing calculator confirms this.
To find the volume, just multiply width by height and then by length.
17 * 15.6 * 8 = 2121.6 inches^3