數學..............急急急 .

1. (-t3-8)-(-7-5t3)
= -t^3 - 8 + 7 + 5t^3
= 4t^3 - 1

2. (3a-4b-c)+(b-4a+2c)
= 3a - 4a - 4b + b - c + 2c
= -a - 3b + c

3. (3xy-4x+5y)+(2xy+5x-2y)
= 3xy - 4x + 5y + 2xy + 5x - 2y
= 5xy + x + 3y

4. (-3t2+t-2)+(t2-2t+3)
= -3t^2 + t - 2 + t^2 - 2t + 3
= -2t^2 - t + 1

5. (5+3y-2y2)+(-5y+y2-4)
= 5 + 3y - 2y^2 - 5y + y^2 - 4
= -y^2 - 2y + 1

6. (4p-5q+5)-(2p-2q-2r)
= 4p - 5q + 5 - 2p + 2q + 2r
= 2p -3q + 2r + 5

7. (3x2-x+5)-(-2x2+x-1)
= 3x^2 - x + 5 + 2x^2 - x + 1
= 5x^2 -2x + 6

8. (t2-3t+2)-(2t+3t2-1)
= t^2 - 3t + 2 - 2t - 3t^2 + 1
= -2t^2 - 5t + 3

9. (-2)(3x-2y+4z)
= -6x + 4y - 8z

10.(-a+b-3c)(-5)
= 5a - 5b + 15c

11.(-4x)(y-7z)
= -4xy + 28xz

12.(a-3b)(-2a)
= -2a^2 + 6ab

13.(5p)(2p+3q-4r)
= 10p^2 + 15pq - 20pr

14.(-2x+3y-z)(-2y)
= 4xy - 6y^2 + 2yz

15.(4a-1)(a-4)
= 4a^2 - 16a - a + 4
= 4a^2 - 17a + 4

16.(2x+3)(5x+2)
= 10x^2 + 4x + 15x + 6
= 10x^2 + 19x + 6

17.(3x-4)(2x+3)
= 6x^2 + 9x - 8x - 12
= 6x^2 + x - 12

18.(5y+2)(-2y+3)
= 10y^2 + 15y - 4y + 6
= 10y^2 + 11y + 6

19.(2x+1)(2x-1)
= 4x^2 - 2x + 2x - 1
= 4x^2 - 1

20.(4p-1)2
= 8p - 2

1:(-t3-8)-(-7-5t3)
=-t3-8+7+5t3
=5t3-t3+7-8
=4t3-1
2:(3a-4b-c)+(b-4a+2c)
=3a-4b-c+b-4a+2c
=3a-4a+b+4b+2c-c
=-a-3b+c
3:(3xy-4x+5y)+(2xy+5x-2y)
=3xy-4x+5y+2xy+5x-2y
=3xy+2xy+5x-4x+5y-2y
=5xy-x+3y或5xy+3y-x
=x(5y-1)+3y或y(5x+3)-x
9:(-2)(3x-2y+4z)
=-2(3x)-2(-2y)-2(4z)
=-6x+4y-8z
10.(-a+b-3c)(-5)
=-5(-a)-5(b)-5(-3c)
=5a-5b+15c
11.(-4x)(y-7z)
=-4x(y)-4x(-7z)
=-4xy+28xz

幫你做幾題,自己好好理解,之後個D數解拆方法都一樣,要自己做,否則數學係唔會進步!

你首先拆括號咪得囉．．．．