The formula of an area of a rectangle:
A = wl
We have l = w - 4 and A = 21.
Substitute:
w(w - 4) = 21 <em>use distributive property</em>
(w)(w) + (w)(-4) = 21
w² - 4w = 21 <em>subtract 21 from both sides</em>
w² - 4w - 21 = 0
w² - 7w + 3w - 21 = 0
w(w - 7) + 3(w - 7) = 0
(w - 7)(w + 3) = 0 ↔ w - 7 = 0 ∨ w + 3 = 0
w = 7 ∨ w = -3 < 0
l = w - 4 → l = 7 - 4 = 3
<h3>Answer: the length = 3 u.</h3>
Answer:
Step-by-step explanation:
5 bags= $12.50
1= ?
$12.50*1= 12.50
$12.50/5= $2.5
$2.5*5=$12.5
$2.5*3= $7.5
3 bags= $7.5
Just put each number in different positions.
425
542
254
All of these numbers are different and use the same 3 digits
Answer:
We have 197 g of Co-60 after 18 months.
Step-by-step explanation:
We can use the decay equation.
Where:
- M(f) and M(i) are the final and initial mass respectively
- λ is the decay constant (ln(2)/t(1/2))
- t(1/2) is the half-life of Co
- t is the time at the final amount of m
<u>Therefore, we have 197 g of Co-60 after 18 months.</u>
I hope it helps you!
