<span>6 + x = 12. To evaluate an algebraic expression, you have to substitute a number for each variable and perform the arithmetic operations. In the example above, the variable x is equal to 6 since 6 + 6 = 12. If we know the value of our variables, we can replace the variables with their values and then evaluate the expression.</span>
Hello there!
Hydrogen has one proton because the number of protons in an atom is equal to the atomic number of the element. S
ince hydrogen's atomic number is 1, it has one proton.
I hope that's help !
Distance = 556 km
Time = 3.4 h
Speed = Distance / Time = 556 / 3.4 = 163.52 km/h
