There are mnemonic acronyms out there for reminding you how to do this. I think of it simply as using the distributive property.
(4x-3)(x+5) = 4x(x+5) -3(x+5)
then again
= (4x² +20x) + (-3x -15)
= 4x² + (20-3)x -15 . . . . . . . combine like terms
= 4x² +17x -15
Answer: 
Step-by-step explanation:
Given
Population of dust particle doubles every 30 minutes
If the initial sample is 21 grams
The model to predict the population will be
Where t=time in hours
A day has 24 hours . So, for 2 days time is 48 hours
Population is given by
<h3>Answer:</h3>
room 3 or 4
<h3>Explanation:</h3>
We assume the inequalities tell the rooms that were checked and found empty.
The solution to 3) is ...
... 2x + 3 > 11
... 2x > 8 . . . . . subtract 3
... x > 4 . . . . . . .divide by 2
The solution to 4) is ...
... -3x > -9
... x < 3 . . . . . . divide by -3
Thus, rooms greater than 4 and less than 3 were found empty. Rooms 3 and 4 were not checked, so either one could hold Nessie.
_____
The other inequalities have solutions that are already covered by the solutions to these.
1) x < -1 . . . . after subtacting 4
2) x > 5 . . . . after multiplying by 5
Answer:
One
Explanation:
3
y
=
18
x
+
21
XXX
⇔
y
=
6
x
+
7
5
y
+
55
=
30
x
XXX
⇔
y
=
6
x
−
11
both equations are linear and they are not co-linear
therefore there is exactly 1 solutio
