數學功課唔識既問題

1. 2a-4b/3a+6b 乘 10b+5a/6b-3a
=2(a-2b)/3(a+2b) X 5(a+2b)/-3(a-2b)
=2/3 X 5/-3
=-10/9

2. x^2 +x/3-3x 除 2x+2/5x-5
=x(x+1)/-3(x-1) X 5(x-1)/2(x+1)
=x/-3 X 5/2
=-5x/6

3. a^2b/4c^3 除 2b^2c/3a 乘 16bc^4/3a^3
=a^2b/4c^3 X 3a/2b^2c X 16bc^4/3a^3
=(a^2b)(3a)(16bc^4) / (4c^3)(2b^2c)(3a^3)
=(48a^3 b^2 c^4)/ (24a^3 b^2 c^4)
=2

4.10/3a 加 5/2a
=20/6a + 15/6a
=35 / 6a

5. y/4(x+y) 減 8+y/4(x+y)
=(y-(8+y))/4(x+y)
=-8 / 4(x+y)
=-2 / x+y

6. 5/a 減 3/a+b
=5(a+b) / a(a+b) - 3a / a(a+b)
=(5-3a) / a(a+b)


7. 2x-5/2(x-1) 減 3x/2(1-x)
=4x(1-x)/2(1-x) + 5/2(1-x) - 3x/2(1-x)
=[4x(1-x)+5-3x] / 2(1-x)
=(-4x^2+x+5)/2(1-x)
=(4x^2-x-5) / 2(x-1)

補充果條咪係第一條囉...