Answer:
C; right answer on Khan Academy
Step-by-step explanation:
Hello from MrBillDoesMath!
Answer:
4( x + 1.5)^2 + 0
Discussion:
4x^2 + 12x + 9 = => factor "4" from first 2 terms
4 (x^2 + 3x) + 9 = => complete the square, add\subtract (1.5)^2
4(x^2 + 3x + (1.5)^2) - 4 (1.5)^2 + 9 =
4 ( x + 1.5)^2 + ( 9 - 4(1.5)^2) = => as (1.5)^2 = 2.25
4 ( x + 1.5)^2 + ( 9 - 4(2.25)) = => as 4 ( 2.25) = 9
4 ( x+ 1.5)^2 + 0
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MrB
Try this solution:
1. Note, that 100 is divisible by 4, and 999 is not divisible by it, only 996. This is an arithmetic sequence.
2. a1;a2;a3;a4;...a(n) the sequence, where a1=100; a2=104; a3=108; a4=112; ... etc., and a(n)=996. n=?
3. using a formula for n-term of the sequence: a(n)=a1+d(n-1), where a(n)=996; a1=100 and d=4 (according to the condition ' is divisible by 4'). Then 100+4(n-1)=996; ⇒ 4n=900; ⇒ n=225 (including 100).
answer: 225
