Question

y a √x and y = 18 when x = 4, then the value
of y is ................. when x=81
(a) 80 (b) 81 (C) 41 (d) 40​

Answer 1

Answer:

$y \alpha \sqrt{x} \\ y = k \sqrt{x} \\ 18 = 2k \\ k = 9 \\ therefore \: y \: = 9 \sqrt{x} \\ put \: x \: = 81 \\ y = 9 \sqrt{81} \\ = 9 \times 9 \\ = 81$

Answer 2

Step-by-step explanation:

option b 81 is the right answer