Question

Mrs. Wilson told her ELA class that students tend to forget 25% of all the vocabulary words they learned the previous week. Students learned 20 words the first week. Which exponential equations describe the number of words forgotten after x weeks. Select all that apply.• y= 20(1+0.25)^x• y= 20×0.75^x• y= 25(1.25)^x• y= 25(1-0.20)^x• y= 20×(1-0.25)^x

Answer 1

We have

20 words the first week

they forget the 25 % of all the vocabulary

The exponential equations that apply are

$y=20(1-0.25)^x$

if we solve the operations inside the brackets

$y=20(0.75)^x$

The answers are the second and fifth options

• y= 20×0.75^x

• y= 20×(1-0.25)^x​