A rectangle has a length of 30 feet less than 6 times its width. If the area of the rectangle is 4836 square feet, find the length of the rectangle.Answer How to enter your answer (opens in new window) 5 PointsКеурасKeyboard Shortcufeet

A rectangle has a length of 30 feet less than 6 times its width If the area of the rectangle is 4836 square feet find the length of the rectangleAnswer How to e class=

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Answer

Step-by-step explanation

Variables

• x: width of the rectangle, in ft

,

• y: length of the rectangle, in ft

Given that the length, y, is 30 feet less than 6 times the width, x, then:

[tex]y=6x-30\text{ \lparen eq. 1\rparen}[/tex]

The area of a rectangle is calculated as follows:

[tex]Area=length{}t\times width[/tex]

In this case, the area is 4836 square ft. Substituting this value and using the before defined variables, we get:

[tex]4836=yx\text{ \lparen eq. 2\rparen}[/tex]

Substituting equation 1 into equation 2:

[tex]\begin{gathered} 4836=(6x-30)x \\ 4,836=6x^2-30x \\ 0=6x^2-30x-4836 \end{gathered}[/tex]

We can solve this equation with the help of the quadratic formula, as follows:

[tex]\begin{gathered} x_{1,2}=\frac{-b\pm\sqrt{b^2-4ac}}{2a} \\ x_{1,2}=\frac{3^0\pm\sqrt{(-30)^2-4\cdot6\cdot(-4836)}}{2\cdot6}\frac{}{} \\ x_{1,2}=\frac{30\pm\sqrt{116964}}{12} \\ x_{1,2}=\frac{30\pm342}{12} \\ x_1=\frac{30+342}{12}=31 \\ x_2=\frac{30-342}{12}=-26 \end{gathered}[/tex]

Given that the width cannot be negative, then the second solution is discarded.

Substituting x = 31 ft into equation 1: