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Brian wants to increase the size of his 3 feet by 6 feet garden.
he wants to increase each side by the same amount to double the area.
find the amount by which he should increase each side. round to the nearest tenth.
Find the area: 3*6 = 18, double the area = 36 sq/ft
Let x = amt to be added to the length and width to double the area
(x+3)*(x+6) = 36
x^2 + 6x + 3x + 18 = 36
x^2 + 9x + 18 - 36 = 0
x^2 + 9x - 18 = 0. the quadratic equation for this
Use the quadratic formula
where a=1, b=9, c=-18
The positive solution
x = 1.7 ft added to each dimension
See if that works: 4.7 * 7.7 = 36.19 ~ 36 sq/ft