中2數學 (代數分式)11題

1) x二次方 - y二次方 / a + b ÷ 7x + 7y / 7a + 7b
= (x+y)(x-y) / (a+b) 乘 7(a+b) / 7(x+y)
= x - y

2) 2x/3a ÷ x二次方/6a二次方 乘 12a/x
= 2x/3a 乘 6a二次方/x二次方 乘 12a/x
=48a二次方/x二次方

3) a/a-b + b/b-a
= a/a-b - b/a-b
=a-b/a-b
=1

4) 4a-5/8a二次方 + -4/12a
= 4a-5/8a二次方 - 1/3a
= 3(4a-5)-8a/24a二次方
=4a-15/24a二次方

5) 3p+3q/7p+7q
= 3(p+q)/7(p+q)
=3/7

6) 2x+1/x-3 乘 2x-6/4x
= 2x+1/x-3 乘 2(x-3)/4x
= 2x+1/2x

7) 6y+12/3y-9 ÷ 4y+8/3
= 6(y+2)/3(y-3) 乘 3/4(y+2)
=3/2(y-3)

8) a二次方/b 乘 x/a ÷ x/b二次方
= a/b 乘 x/a 乘 b二次方/x
=ab

9) a/a-b - b/b-a
= a/a-b + b/a-b
= a+b / a-b

10) 1/x-1 - 1/x+1
= x+1-(x-1) / x二次方-1
= 2 / x二次方-1

11) 1/x-1 + 1/x+1 + 3x-1/1-x二次方
= 2 / x二次方-1 - 3x-1/x二次方-1
= 2-3x+1 / x二次方-1
= 3-3x / x二次方-1
= -3(x-1) / (x+1)(x-1)
= -3/x+1

今次的比上次的還要淺很多......

1. 7(x-y)
3. 1
5. 3/7
7. 3/2(y-3)
9. a+b/a-b