Correct Question:
5 (u + 1) - 7 = 3 (u - 1) + 2u.
Solve for u
Answer:
See explanation below
Step-by-step explanation:
In this given question, we are required to find u.
Given the equation:
5 (u + 1) - 7 = 3 (u - 1) + 2u
Required:
Solve for u
To find u, first simplify both sides individually.
Simply 5 (u + 1) - 7:
Expand the parenthesis:
5u + 5 - 7
Collect like terms:
5u - 2
<em>Simplify 3 (u - 1) + 2u:</em>
Expand the parenthesis:
3u - 3 + 2u
Collect like terms:
3u + 2u - 3
5u - 3
Bring both simplified equations together:
5u - 2 = 5u - 3
5u - 5u - 2 = -3
-2 = -3
Since -2 ≠ -3, there is no solution.
Therefore, we can say the equation is invalid.
Don’t follow the link he or she gave you.
Answer:
The amount invested at 5% was $39,000 and the amount invested at 7% was $11,000
Step-by-step explanation:
we know that
The simple interest formula is equal to

where
I is the Final Interest Value
P is the Principal amount of money to be invested
r is the rate of interest
t is Number of Time Periods
Let
x-----> the amount invested at 5%
50,000-x -----> the amount invested at 7%
so

substitute in the formula above

solve for x



therefore
The amount invested at 5% was $39,000 and the amount invested at 7% was $11,000
Option B:

Solution:
Given sound level = 120 decibel
To find the intensity of a fire alarm:

where 
Step 1: First divide the decibel level by 10.
120 ÷ 10 = 12
Step 2: Use that value in the exponent of the ratio with base 10.

Step 3: Use that power of twelve to find the intensity in Watts per square meter.


Now, do the cross multiplication,




Option B is the correct answer.
Hence
.