3squared times 4 divided by 2 over square root of 9-2 square, and then the sum multiplied by the cube root of 25

So you want to remember PEMDAS. 
So first you would do the exponents and the square roots. Since the -3 isn't in a parenthesis it would be -9.  -9 x 4 divided by 2 / 3 - 4

Next you want to do the multiplication and then division in the numerator and just solve the denominator. it would look like this: -18 / -1 which is 18

then the cube root of 25 is a weird number so just leave it in that form and multiply which is 52.63 rounded

hope this helps!

The variables should add up to equal 1