The sum of two numbers is 3. five times the larger number plus four times the smaller number is 29. find the numbers

The table above shows approximate conversions from gallons to liters. what is the value of x?

What does x = in this equation x+3+2x=x+5

He mass of a single atom of carbon can be found by dividing the atomic mass (12.01 g) by 6.022 x 10^23. which is the mass of a single carbon atom, correctly written in scientific notation with the correct number of significant figures?