<h3><u>
Answer:</u></h3>
<h3><u>
Step-by-step explanation:</u></h3>
<em>There can be many ways to find the number.</em><em> I have found the number with the help of fractions and multiplication. </em><em>Below is the solution to your problem.</em>
- 80 = 20/100
- => 5 x 80 = 20 x 5/100
- => 400
<h3><u>
Conclusion:</u></h3>
<em>Hence, 80 is 20% of 400. </em><em>I hope my method helped you.</em>

Answer:
-90
Step-by-step explanation:
Check the picture below.
the piecewise function, has two subfunctions or behaviours, one if x < 1, meaning less, not equals, but less than 1, so it doesn't include one, so it has a "hole" on that endpoint.
and the second behaviour of the piecewise is if x ⩾ 1, larger or equals than 1, so it includes 1, so it has a solid ball on that endpoint.