Question

the base of a rectangle is 5cm more than its breadth its area is 84sq cm find its dimensions

Answer 1

Let B= x then L= x+5..... Area = L×B...... But area is given to be 84 sq. ..... Therefore L×B= 84..........x×(x+5)=84........x^2+5x=84........ x^2+5x-84=0........... BY Quadratic Formula........D= b^2-4ac...........5^2-4*1*-84........=25+336= 361= √D= 19......... x = -b+-√D /2a= -5+-19/2............. Now x has two values... -5-19/2= -24/2= -12........ And x = -5+19/2= 14/2= 7....... Sides cannot be negative so x= 7. .............. Now, B = x= 7 cm..... And L= x+5= 7+5= 12 cm..

Answer 2

Let breadth = x cm
Length = (x +5) cm
Area = 84 sq cm
x(x+5)=84
x²+5x-84 = 0
(x+12)(x-7) = 0
x = 7 
So, breadth = 7 cm
length = 12 cm