25 is the answer hope it helps
Answer:
18 minutes
Step-by-step explanation:
A = A₀ (½)^(t / T)
where A is the final amount,
A₀ is the initial amount,
t is the time,
and T is the half life.
A = 140 when t = 10. Solve for the half life:
140 = 700 (½)^(10 / T)
0.2 = ½^(10 / T)
log 0.2 = (10 / T) log 0.5
10 / T = 2.32
T = 4.31
When A = 40, t is:
40 = 700 (½)^(t / 4.31)
0.057 = ½^(t / 4.31)
log 0.057 = (t / 4.31) log 0.5
t / 4.31 = 4.13
t = 17.8
Rounded to the nearest whole number, it takes 18 minutes.
17²-8²=225
√225= 15
therefore both x and y are 15 ft
let length = x
width is 7 feet less than length
width = x-7
area = length *width
area = x(x-7)
170=x²-7x
x²-7x-170=0
x²-17x+10x-170=0
x(x-17)+10(x-17)=0
(x-17)(x+10)=0
x=17 or x=-10
since length cannot be negative so x=17
and width =x-7 =17-7=10
length =17 feet and width =10 feet
Answer: 6units
Step-by-step explanation:
Since it is a regular polygon, and it has 3 equal sides it means the polygon is a quadrilateral.
From the diagram,
5 - 2x = -4x + 9 ( side of quadrilateral )
Solving for x in the equation
-2x + 4x = 9 - 5 ( collection of like terms in simple linear equation )
2x = 4
Divide through by the coefficient of x which is 2
x = 2.
Therefore, the perimeter of the polygon which equals to the total length of the polygon is
Perimeter = 2 + 2 + 2
= 6units
