Answer:
................ hope this helps you
Answer:
4x² -4xy -4y -4
Step-by-step explanation:
In this case, a= 2x -y and b= y +2.
(2x -y)² -(y +2)²
= (2x -y +y +2)[2x -y -(y +2)]
= (2x +2)(2x -y -y -2)
= (2x +2)(2x -2y -2)
= 2x(2x) +2x(-2y) +2x(-2) +2(2x) +2(-2y) +2(-2) <em>(expand)</em>
= 4x² -4xy -4x +4x -4y -4
= 4x² -4xy -4y -4
Alternatively, start by expanding the brackets.
(2x -y)² -(y +2)²
= 4x² -4xy +y² -(y² +4y +4)
= 4x² -4xy +y² -y² -4y -4 <em>(</em><em>expand</em><em>)</em>
= 4x² -4xy -4y -4 <em>(</em><em>simplify</em><em>)</em>
Answer:
<u>The exponential model is: Cost after n years = 400 * (1 + 0.02)ⁿ</u>
Step-by-step explanation:
1. Let's review the information given to us to answer the question correctly:
Cost of the TV set in 1999 = US$ 400
Annual increase rate = 2% = 0.02
2. Write an exponential model to represent this data.
Cost after n years = Cost in 1999 * (1 + r)ⁿ
where r = 0.02 and n = the number of years since 1999
Replacing with the real values for 2020, we have:
Cost after 21 years = 400 * (1 + 0.02)²¹
Cost after 21 years = 400 * 1.5157
Cost after 21 years = $ 606.28
The TV set costs $ 606.28 in 2020.
<u>The exponential model is: Cost after n years = 400 * (1 + 0.02)ⁿ</u>
Go up by 2 each time. answer is 20