f(-3)= f(t)=Square root of t^2 t 1

Please clarify (use parentheses to indicate what is under the radical).

As said by Perito, it's confusing what you have typed..

I'll give you an example;

say you have f(x) = 2x - 3

Then, f(1) would be f(1)= 2(1) - 3 = -1

See what I've done? I;ve replaced the 'x' by 1 everywhere. When I replace 'x' by a number or any other variable in the original function, all the 'x' are replaced by the number or the variable.

Another one; f(y) = 2x + 5
f(1) = 2(1) +5 = 7
f(2) = 2(2) + 5 = 9
f(a) = 2(a) +5 = 2a + 5