What is the value of a^2 - b^2?
(1) b=4-a
(2) a - 3 = b
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(1) b=4-a
(2) a - 3 = b
[Reveal] Spoiler:
I understand that a^2- b^2 can be factored as (a+b)(a-b) and that statements 1 and 2 can be rewritten as a+b=4 and a-b=3. Therefore, correct answer should be C since the product of these two gives you 12.
However, I choose D when I did this problem.
a^2 -b^2 ----factored to---> (a+b)(a-b)
I then plugged in the value of b into each of these factors (a+4-a)(a-((4-a)). I ended up with a value of a=2
Why is this not allowed?
However, I choose D when I did this problem.
a^2 -b^2 ----factored to---> (a+b)(a-b)
I then plugged in the value of b into each of these factors (a+4-a)(a-((4-a)). I ended up with a value of a=2
Why is this not allowed?