我想問下呢4條數學題點做..

-4 (- 10 - 5x + 2x的2次方+ 3x的3次方) + 2 (4x - 6x的2次方- x的3次方- 4)
= 40 + 20x -8x的2次方- 12x的3次方+ 8x - 12x的2次方 - 2x的3次方 - 8
= 32 + 28x - 20x的2次方 - 14x的3次方

25x - 19 - [3 - (4x - 5)] = 3x - (6x - 5)
25x - 19 - 3 + 4x - 5 = 3x - 6x + 5
29x - 27 = - 3x + 5
32x = 32
x = 1

4(3+x) - 3(2x-5) = 6 - x - 2(3-x)
12 + 4x - 6x + 15 = 6 - x - 6 + 2x
- 2x + 27 = x
3x = 27
x = 9

4(a - 2b - 3c - 4d - 5e) - 4(- a - 2b - 3c - 4d - 5e)
= 4 [(a - 2b - 3c - 4d - 5e) - (- a - 2b - 3c - 4d - 5e)]
= 4 (a - 2b - 3c - 4d - 5e + a + 2b + 3c + 4d + 5e)
= 4 (2a)
= 8a

-4(-10-5x+2x的2次方+3x的3次方)+2(4x-6x的2次方-x的3次方-4)
=-4(-10-5x+2x^2+3x^3)+2(4x-6x^2-x^3-4)
=40+20x-8x^2-12x^3+8x-12x^2-2x^3-8
=32+28x-20x^2-20x^3
=4(8+7x-5x^2-5x^3)

25x-19-[3-(4x-5)]=3x-(6x-5)
25x-19-3+4x-5=-3x+5
32x=32
x=1

4(3+x)-3(2x-5)=6-x-2(3-x)
12+4x-6x+15=6-x-6+2x
27-2x=x
3x=27
x=9

4(a-2b-3c-4d-5e)-4(-a-2b-3c-4d-5e)
=4a-8b-12c-16d-20e+4a+8b+12c+16d+20e
=8a