Answer:
Step-by-step explanation:
x = pens and y = pencils
4x + 5y = 6.71....multiply by 5
5x + 3y = 7.12....multiply by -4
--------------------
20x + 25y = 33.55 (result of multiplying by 5)
-20x - 12y = - 28.48 (result of multiplying by -4)
--------------------add
13y = 5.07
y = 5.07 / 13
y = 0.39 <=== cost of a pencil
4x + 5y = 6.71
4x + 5(0.39) = 6.71
4x + 1.95 = 6.71
4x = 6.71 - 1.95
4x = 4.76
x = 4.76/4
x = 1.19 <==== cost of a pen
Let's assume
It started in 2000
so, t=0 in 2000
we can use formula
we can plug value
In 2005, the same survey was made and the total amount of gamma ray bursts was 7.3 million
so, at t=2005-2000=5
P(t)=7.3 million
we can plug value and then we can solve for r
now, we can plug back
now, we have
P(t)=1 billion =1000 million
so, we can set it and then we can solve for t
approximately
Year is 2000+192
year is 2192................Answer
f(x) = 6x + 9 ← in functional notation
let y = f(x) and rearrange the equation making y the subject
add 6x + 9 to both sides
y = 6x + 9
thus f(x) = 6x + 9