Question

width of a rectangle is 15cm less tahn 3 times the length. if the area is 42 square cm. find the dimensiins of the rectangle.

Answer 1

Let length be 'L'
      breadth be 'b'.
b is 15cm less than 3 times the length.
∴ b = 3(L) - 15.
Area          = 42 sq. cm
L× b          = 42
L× 3L - 15 =42                                              [(∵b=3(L) - 15)]
3L²            = 42-15
3L²            =27
  L²            =27÷3
  L²            = 9
∴ L            = √9
⇒L = Length = 3 cm.
∴ b= Breadth= 3(L)-15
                     =3(3) - 15
                      = 9 - 15
⇒Breadth = -6 cm.