1) x = 2.5 when y = -5
2) x = 0.25 when y = - 1
Solution:
Given that , we have to use direction variation formula.
Now, we know that, direct variation formula is y = kx, where k is proportionality constant.
1) If y=4 when x= -2, find x when y= -5
Put y = 4 and x = -2 in y = kx
4 = k(-2)
k = - 2
Then, when y = -5
-5 = (- 2)x
x = 5/2
x = 2.5
2) If y=20 when x = -5, find x when y= -1
Put y = 20 and x = -5 in y = kx
20 = k(-5)
k = - 4
Then, when y = -1
-1 = (- 4)x
x = 1/4
x = 0.25
Hence, 1) x = 2.5 when y = -5 and 2) x = 0.25 when y = - 1