The equation formed by multiplying each root of `ax^(2) + bx+ c = 0" by "2 " is "x^(2) = 36x + 24 =0`
The area of a rectangle whose length is five more than twice its width is 75 square unit. The length is

Options

A. 5 unit
B. 10 unit
C. 15 unit
D. 20 unit

Answer

C

Explanation

Let width of the rectangle =x
so length `=2x+5`
Given, Area of rectangle = 75
` rArr x(2x+5) = 75 rArr 2x^(2) + 5x - 75 = 0 `
` rArr 2x^(2) + 15 x - 10x -75 = 0 `
`rArr (x-5) (2x + 15)=0`
` rArr x= 5, -15/2`
Since, width can not be negative.
` :. x=5`
` :. "length" = 2x+5 = 15`