f.4 maths
22. if ax^3 +5x^2 +bx -6 is divisible by 2x^2 +x -3 , find the values of a and b
回答 (2)
ax³+5x²+bx−6=2x²+x−3
ax³+5x²+bx−6=(2x+3)(x−1)____(1)
Put x=−3/2 : 9a+4b−14=0___(2)
Put x=1 : a+b−1=0 ___(3)
(2)−4(3): 5a−10=0 ⇒ a=2
∴a=2 , b=−1
2010-05-13 13:23:01 補充:
ax³+5x²+bx−6=(2x²+x−3)·Q(x) ,where Q(x) is the quotient
ax³+5x²+bx−6=(2x+3)(x−1)·Q(x)____(1)
收錄日期: 2021-04-15 23:57:00
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