Some function and domain questions, attachments below

• f(x+3) = 4x + 12, you can factorize 4x + 12 like this:

Like this you can replace x+3 for and you will get the formula you need for f(x):


•

since the radicand can only be 0 or a positive number, x+4 and x-9 must both be 0 or positive


and

with this we know that x has to be:

and the domain is: [9,∞)

The first one is 2/3the second is 1/160the third is 4/125

The answers are 20,30,80,180,960,890,1230,4560. on the first row