P.95
It is given that 2x^3+9x^2-8x-k is divisible by x+5
a)Find the value of k.
b)Hence,factorize 2x^3+9x^2-8x-k completely.
f.4 maths *e
2007-10-23 8:04 am
回答 (2)
2007-10-23 8:11 am
✔ 最佳答案
(a) Let f(x) = 2x^3+9x^2-8x-kf(-5) = 0
2(-5)^3 + 9(-5)^2 - 8(-5) - k = 0
-250+225+40-k = 0
k = 15
(b) By long division, 2x^3+9x^2-8x-15 = (x+5)(2x^2-x-3) = (x+5)(2x-3)(x+1)
2007-10-23 8:15 am
a, Let x be( -5)
2x^3+9x^2-8x-k=0
-2*125+9*25+40-k=0
k=15
b. 2x^3+9x^2-8x-k
=2x^3+9x^2-8x-15
=(x+5)(2x^2-x-3)
=(x+5)(x+1)(2x-3)
2x^3+9x^2-8x-k=0
-2*125+9*25+40-k=0
k=15
b. 2x^3+9x^2-8x-k
=2x^3+9x^2-8x-15
=(x+5)(2x^2-x-3)
=(x+5)(x+1)(2x-3)
收錄日期: 2021-04-13 18:12:00
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