Question

the area of a rectangle whose length is five more than twice its width is 75 cm². calculate its length

Answer 1

Let the width of the rectangle = x units

Length = (2 x + 5) units

According to the question,

Area = x(2x + 5)

=> 75 = 2x2+5x2x2+5x

=> 2x2+5x−75=02x2+5x−75=0

=> 2x2+15x−10x−75=02x2+15x−10x−75=0

=> x(2x+15)-5(2x+15)=0

=> (2x+15)(x-5)=0

=> x = 5 and −152−152

Width cannot be negative.

Width = 5 units

Length=2x+5 =2×5+52×5+5=15 units

Perimeter of the rectangle

= 2(15 + 5) = 40 units