A. 3x2 + 9x - 6
B. 3x2 + 2x + 26
C. 26 + x
D. 3x2 + 21x + 26
If f (x) = 3x2 + 9x - 4, find and simplify f (2 + x).?
2016-06-20 7:56 pm
回答 (5)
2016-06-20 8:01 pm
f(x) = 3x² + 9x - 4
f(2 + x)
= 3(2 + x)² + 9(2 + x) - 4
= 3(4 + 4x + x²) + 9(2 + x) - 4
= 12 + 12x + 3x² + 18 + 9x - 4
= 3x² + (12x + 9x) + (12 + 18 - 4)
= 3x² + 21x + 26
...... The answer is : D. 3x² + 21x + 26
f(2 + x)
= 3(2 + x)² + 9(2 + x) - 4
= 3(4 + 4x + x²) + 9(2 + x) - 4
= 12 + 12x + 3x² + 18 + 9x - 4
= 3x² + (12x + 9x) + (12 + 18 - 4)
= 3x² + 21x + 26
...... The answer is : D. 3x² + 21x + 26
2016-06-20 8:15 pm
f(2+x) = 3(2+x)^2 + 9(2+x) - 4 = 3(4+4x+x^2) + 18 +9x - 4 =
12 + 12x + 3x^2 +18 + 9x - 4 = 26 + 21x + 3x^2 which is D.
12 + 12x + 3x^2 +18 + 9x - 4 = 26 + 21x + 3x^2 which is D.
2016-06-20 8:08 pm
f(2+x) = 3(2+x)^2 +9(2+x) - 4
= 3( 4+4x+x^2) + 18+9x-4
= 12+12x+3x^2+18+9x-4
= 3x^2+21x+26
= 3( 4+4x+x^2) + 18+9x-4
= 12+12x+3x^2+18+9x-4
= 3x^2+21x+26
2016-06-20 8:00 pm
D. 3x2 + 21x + 26
f (x) = 3x2 + 9x - 4,
f(x + 2) = 3(x + 2)^2 + 9(x + 2) - 4
= 3( x^2 + 4x + 4) + 9x + 18 - 4
= 3x^3 + 12x + 12 + 9x + 14
= 3x^2 + 21x + 26
What is wrong with this answer?
f (x) = 3x2 + 9x - 4,
f(x + 2) = 3(x + 2)^2 + 9(x + 2) - 4
= 3( x^2 + 4x + 4) + 9x + 18 - 4
= 3x^3 + 12x + 12 + 9x + 14
= 3x^2 + 21x + 26
What is wrong with this answer?
2016-06-20 7:57 pm
Ever heard of a calculator?
收錄日期: 2021-04-18 15:16:08
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20160620115604AAmlXbo