Answer:
x = 1
Step-by-step explanation:
f(x) = 3 or y = 3
Locate y = 3 on the y- axis , go horizontally across to meet the line at (1, 3 )
Then
When f(x) = 3 , x = 1
Are you sure the options are what u have written above? because sqrt of 5x=sqrt of 5x,
sqrt of 20x=2•sqrt of 5x,and sqrt of 80x= 4•sqrt of 5x..