Answer:
42.6cm
Step-by-step explanation:
The sum total of all the sides of the shape is the perimeter of the shape. Hence;
Perimeter = x+3 + 4 + x+9 + 2x+5
Perimeter = 4x + 21
Given
Area of the figure = 75cm^2
Area = (x+3)(2x+5) + (2x+1)(6)
75 = 2x²+5x+6x+15+12x+6
75 = 2x²+23x+21
2x²+23x+21-75 = 0
2x²+23x-54 = 0
x = -23±√23²-4(2)(-75)/4
x = -23±√529+600/4
x = -12±√1129/4
x = -12+33.6/4
x = 21.6/4
x = 5.4
Recall that;
Perimeter = 4x+21
Perimeter = 4(5.4) + 21
Perimeter = 21.6+21
Perimeter = 42.6cm
Hence the perimeter is 42.6cm
Answer: 7 years
Step-by-step explanation:
= In2 / ∧
since the half life is given , we have :
22 = In 2/ ∧
∧ = In2/22
∧ = 0.032
Recall the formula for half life:
= 
Therefore:
0.80 = 
Take the In of both sides
In 0.80 = - 0.032t
t = In 0.80 / - 0.032
t = 7 years
