Alright, let's solve this step by step.
### Step 1: Decrease 350 by 15%
To decrease 350 by 15%, you first need to calculate 15% of 350.
[tex]\[
15\% = \frac{15}{100} = 0.15
\][/tex]
Now multiply 350 by 0.15 to find the amount to decrease:
[tex]\[
0.15 \times 350 = 52.5
\][/tex]
Subtract this value from the original number (350):
[tex]\[
350 - 52.5 = 297.5
\][/tex]
Thus, after decreasing 350 by 15%, the result is 297.5.
### Step 2: Add the result to 12.421
Next, we add 297.5 to 12.421:
[tex]\[
297.5 + 12.421 = 309.921
\][/tex]
So, 297.5 added to 12.421 is 309.921.
### Step 3: Calculate the difference between [tex]$\frac{43}{4}$[/tex] and [tex]$\frac{3}{5}$[/tex]
First, convert both fractions to decimal form:
[tex]\[
\frac{43}{4} = 10.75
\][/tex]
[tex]\[
\frac{3}{5} = 0.6
\][/tex]
Now subtract [tex]$\frac{3}{5}$[/tex] from [tex]$\frac{43}{4}$[/tex]:
[tex]\[
10.75 - 0.6 = 10.15
\][/tex]
So the difference between [tex]$\frac{43}{4}$[/tex] and [tex]$\frac{3}{5}$[/tex] is 10.15.
### Final Results
1. After decreasing 350 by 15%, the result is 297.5.
2. Adding 297.5 to 12.421 gives 309.921.
3. The difference between [tex]$\frac{43}{4}$[/tex] and [tex]$\frac{3}{5}$[/tex] is 10.15.
Therefore, the detailed solution yields the following results:
[tex]\[
(297.5, 309.921, 10.15)
\][/tex]