Question

The area of a rectangle is given by the equation 2*l (squared) -5*l = 18 , in which l is the rectangle's length. what is the length of the rectangle.​

Answer 1

Answer: L=4.5

Explanation:

`2L^2-5L=18 \ \ \ \ \ L > 0\\2L^2-5L-18=18-18\\2L^2-5L-18=0\\2L^2-5L-4L+4L-18=0\\(2L^2-9L)+(4L-18)=0\\2L*(L-4.5)+4*(L-4.5)=0\\(L-4.5)*(2L+4)=0\\L-4.5=0\\L_1=4,5\\2L+4=0\\2L+4-4=-4\\2L=-4\\`

Divide both parts of the equation by 2:

`L_2=-2\\otin\ (L > 0)`