Which expression is equivalent to 9+24

When i add money am i supposed to make it like this 7+12 or 7.00+12.00 because i got 19 dollars for my answer

Is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis.

Which steps could be part of the process in algebraically solving the system of equations, y+5x=x^2+10 and y=4x-10