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Answer:
Ans. of 6 question
Value of k is 7 or -3
Step-by-step explanation:
Given: A(k, -5) , B(2,7)
Distance between the pts. is 13 units
To find: Value of k
Solution:
By distance fromula
AB = √(x2-x1)^2 + ( y2- y1)^2
13 = √[2-k]^2 + [7-(-5)]^2
13 = √(2-k)^2 + (7+5)^2
13 = √(2-k)^2 + (12)^2
13 = √ [(2)^2 - 2(2)(k) + (k)^2] + 144
13 = √ 4 - 4k + k^2 + 144
13 = √ k^2 - 4k + 148
squaring oth sides
169 = k^2 - 4k + 148
169 - 148 = k^2 - 4k
21 = k^2 - 4k
k^2 - 4k - 21 = 0
by splitting middle term
k^2 - 7k + 3k - 21 = 0
k (k - 7) + 3(k - 7) =0
(k - 7) (k + 3) = 0
k - 7 =0 OR k + 3 = 0
k =7 OR. k = -3
Therefore, the value of k is 7 or -3 .
I hope this will help you...