Question 1
Answer: C) First and last term
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Step-by-step explanation:
Recall that (a+b)^2 = a^2+2ab+b^2 when using the FOIL rule. To go in reverse, to factor, we would apply the square root to the a^2 to get 'a', and also apply the square root to b^2 to get b. This then helps form the a+b shown on the left side.
The next question will go over a specific example of what is going on. Note that in question 2, the use of the phrasing "root of the first term" and "root of the last term" which helps reinforce we have the correct answer for problem 1.
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Question 2
Answers:
- Root of the first term = 9v
- Root of the last term = 10
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Step-by-step explanation:
Apply the square root to the first term to get
sqrt(81v^2) = sqrt( (9v)^2 ) = 9v
Or you could note that (9v)^2 = (9v)*(9v) = 81v^2, from which we work in reverse when applying the square root.
Similarly, the square root of the last term is
sqrt(100) = sqrt(10^2) = 10
So that's why the answers are 9v and 10 for the blanks.
We can say:
(a+b)^2 = a^2 + 2ab + b^2
(9v+10)^2 = (9v)^2 + 2(9v)(10) + (10)^2
(9v+10)^2 = 81v^2 + 180v + 100