Answer:
Breadth = 8 cm
Length = 17 cm
Step-by-step explanation:
Given rectangle:
Breadth = x cm
Length = x + 9 cm
Area = length * breadth
= x * (x + 9)
= x² + 9x
Rectangle with length and breadth increased:
Breadth = x + 3 cm
Length = x + 9 + 3 = x + 12 cm
Area = 84 + (x² + 9x) cm²
(x +3) * (x +12) = 84 + x² + 9x
Use FOIL method
x*x + x*12 + 3*x + 3*12 = 84 + x² + 9x
x² + 12x + 3x + 36 = 84 + x² + 9x {add the like terms}
x² + 15x + 36 = 84 + x² + 9x
x² + 15x + 36 - 84 - x² - 9x = 0
6x - 48 = 0
6x = 48
x = 48/6
x = 8
Breadth = x = 8 cm
Length = x + 9 = 8 +9 = 17 cm
