MATHS QUESTION

hung

2008-02-14 8:39 pm

4)given f(x) =(x-3)(2x^2+4x-5)-2(x-1) find the coefficient of x^2 and the coefficient of x
5) subtract x^5-x^4-3x^2+7x+1 from the product of x^2+1 and x-x^2+7x^5-2x^3+3x^4+6 the result is another polyminal find its constant term and the coefficient of x^4
6) factorize 3x^2+13x+12 using upper ans to express 31312 as a producy of prime factor

回答 (1)

myisland8132

2008-02-14 11:20 pm

✔ 最佳答案

4)given f(x) =(x-3)(2x^2+4x-5)-2(x-1) find the coefficient of x^2 and the coefficient of x
f(x)
=(x-3)(2x^2+4x-5)-2(x-1)
=2x^3+4x^2-5x-6x^2-12x+15-2x+2
=2x^3-2x^2-19x+17
the coefficient of x^2 is -2 and the coefficient of x is -19
5) subtract x^5-x^4-3x^2+7x+1 from the product of x^2+1 and x-x^2+7x^5-2x^3+3x^4+6 the result is another polyminal find its constant term and the coefficient of x^4
(x^2+1 )(x-x^2+7x^5-2x^3+3x^4+6)-( x^5-x^4-3x^2+7x+1)
constnt term
=6-1
=5
coefficient of x^4
=(-1)+3-(-1)
=3
6) factorize 3x^2+13x+12 using upper ans to express 31312 as a producy of prime factor
3x^2+13x+12
=(x+3)(3x+4)
sub x=100
31312
=(103)(304)
=2^4*19*103

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