F3 math(20點)

2013-02-17 10:10 pm

Find the value of a in the following cases

1) G(7,a), H(5,4) ;mGH=3

2) A(-4,-3), B(a,4);mAB=十分七

3)M(a,0), N(-7,-8);mMN=4

回答 (2)

2013-02-17 10:23 pm

✔ 最佳答案

1 (a - 4)/(7 - 5) = 3

(a - 4) = 6

a = 10

2 (4 +3)/(a + 4) = 7/10

a + 4 = 10

a = 6

3 (0 + 8)/(a + 7) = 4

8 = 4(a + 7)

a + 7 = 2

a = -5

👍 0 👎 0

2013-02-18 12:42 am

Ans 1) mGH=(a-4)/(7-5)=3
a-4=3×2
a=10
Ans 2) mAB=(﹣3－4)/(﹣4－a)= 7/10
-7=(7/10)(-4-a)
a=6
Ans 3) mMN=(0-(-8))/(a-(-7))=4
8=4a+28
a=-5

👍 0 👎 0