Here’s a simple example of a function: A dozen always consists of 12 units. So, if you were buying two dozen eggs, you’d be buying

In the following practice questions, you have to use a function to find a missing value in a table, and then figure out how energy is affected by a change in mass, based on Einstein’s equation (that is, function) for the speed of light.

## Practice questions

*The first question refers to the following table.*

- Herman developed the following function to amuse himself:
*F*= 2*a*+ 3*b*^{2}– 2*ab.*He kept track of his results in this table. Using Herman’s function, what is the value of*x?***A.**53**B.**–82**C.**88**D.**30 - Consider the equation
*E*=*mc*^{2}. If the value of*m*triples and the value of*c*remains constant, the effect on*E*would be how many times larger?**A.**9 times larger**B.**27 times larger**C.**3 times larger**D.**the same

## Answers and explanations

**The correct answer is Choice (D).**Using Herman’s function,

*x*= 2(3)– 3(4)(4) – 2(3)(4) = 6 + 48 – 24 = 30.**The correct answer is Choice (C).**This question tests your knowledge of equations by asking you to analyze how a change in one quantity in an exponential equation,

*E*=*mc*^{2}, results in a change in another quantity. The variation between*E*and*m*in this function is linear and direct, which means that whatever happens to*m*also happens to*E*. If*m*is 3 times larger, so is*E*.