數學問題_高手快入

1.5x^3+12x-1
2.4b^4-6a^2-4a
3.冇得計(題目就係答案)
4.3a^3+6a^2-4a
5.冇得計(題目就係答案)
6.冇得計(題目就係答案)
7.冇得計(題目就係答案)
8.3a^2-5a-2
9.2x^4-5x^3+5x^2+4x-1
10.6x^2-2x+16

(1) (-2x^3 +6x -3) + (7x^2 -6x +2)
= -2x^3 +6x -3 + 7x^2 -6x +2
= 5x^3 – 1

(2) (b^4 -7b^2 +1) – (3b^4 -2b^2 +6)
= b^4 -7b^2 +1 – 3b^4 +2b^2 -6
= -2b^4 – 5b^2 – 5

(3) -3xy^2z+6x^2yz^2 -9xy^2z^2
= 3xyz (-y +2xz -3yz)

(4) 5a^3 – a) + (6a^2 -7x +1) – (2a^3 +4x 11)
= 5a^3 – a + 6a^2 -7x +1 – 2a^3 -4x +1
= 3a^3 +6a^2 – 4a + 2

(5) x^2 – 36 = (x +6) (x – 6)

(6) 3a^2b – 6ab^2 = 3ab(a – 2b)

(7) x^2 – 6a + 9 = (x – 3)(x – 3)

(8) (3a +1) (a – 2) = 3a^2 -5a – 2

(9) (2x^2 – 3x +1)(x^2 –x – 1)
= 2x^4 -2x^3 -2x^2 -3x^3 +3x^2 +3x + x^2 –x – 1
= 2x^4 -5x^3+ 2x^2 +2x– 1

(10) 2x^2 -4x^2 +3x – 5x +9 + 7
= -2x^2 -2x +16