Question 54567
Im not understanding this function stuff. Can someone please explain it to me. Here is an example problem. y^2=x+1 I know that you enter a number into one of the variables and solve for the other variable, but Im not sure what makes a problem like this functional or non functional. 
IF YOU KNOW SUBSTITUTION OF VALUES FOR X AND FINDING Y ,THEN IT IS SIMPLE
TEST WHETHER YOU GET A UNIQUE OR MULTIPLE VALUES FOR Y FOR A PARTICULAR VALUE OF X...IF YOU GET UNIQUE VALUE THEN IT IS A FUNCTION .OTHERWISE IT IS NOT.
IN GENERAL IF Y1 IS NOT EQUAL TO Y2 THEN X1 SHOULD NOT BE EQUAL TO X2 FOR IT TO BE A FUNCTION .OTHERWISE NOT.NOTE THAT IT DOES NOT MATTER THE OTHERWAY AROUND..THAT IS X1 AND X2 CAN HAVE SAME Y VALUE ..THAT IS EVEN IF Y1=Y2, X1 MAY NOT BE EQUAL TO X2. 
SEE FOLLOWING EXAMPLES 
EX.1... Y = X+2...WE KNOW FOR CERTAIN HERE THAT IF Y1 IS NOT EQUAL TO Y2,X1  WILL NOT BE EQUAL TO X2..HENCE ITIS A FUNCTION
EX.2... Y=X^2...HERE ALSO IF Y1 IS NOT EQUAL TO Y2..THEN X1 WILL NOT BE EQUAL O X2.SO IT IS A FUNCTION.SEE THAT HERE X1=+2 AND X2=-2 HAVE SAME Y VALUE +4..IT IS OK FOR A FUNCTION.THE OTHER WAY ROUND IS NOT ALLOWED.
EX.3.....Y = + OR - SQUARE ROOT OF (X)...THIS IS NOT A FUNCTION.SINCE 
X =4 GIVES RAISE TO 2 DIFFERENT VALUES OF Y NAMELY +2 AND -2...IT IS NOT UNIQUE.HENCE THIS IS NOT A FUNCTION.
NOW I THINK YOU CAN ANSWER YOUR PROBLEM WITH THIS TEST AND EXAMPLES