Question

a rectangle shape whose length is 4 inches less than twice its width. the area is 30 square inches. whats the dimension

Answer 1

Using the given information, we can say the following:
Width (W) = x
Length (L) = (2x - 4)
Area of Rectangle = L × W
Using this, we can formulate an equation for rectangle in question:
x(2x - 4) = 30
Expand and move everything to one side:
2x² - 4x - 30 = 0
Simplify by dividing everything on both sides by 2:
x² - 2x - 15 = 0
Factorise:
(x + 5)(x - 3) = 0
Set each factor equal to 0 and solve for x:
x + 5 = 0
x = -5 (a dimension cannot be negative so this is not the solution we want)
x - 3 = 0
x = 3 (this is the solution)
x = W = 3"
L = 2x - 4
L = 2(3) - 4
L = 2"

So, the length the rectangle is 2" and the width is 3"