Solving & Graphing Quadratic Equation

Question

School of electronics P=i^2(20) represent power in DC circuit with a resistance of 20 ohms, p is the power (in Watts), and I (in amps) is the current. (Note: This relationship is of the same form as many of the quadratic you wil see in this chapter; in particular y=x^2(20). As a result the methods you use to solve similar quadratic would apply here.) if the power is 168.2 Watts, what is the current?

Answer 1

Using the formula P = I^2 * 20 and substituting 168.2 for P you obtain 168.2 = I^2 * 20.

 

Dividing both sides by 20 yields 8.41 = I^2. I must be 2.9 amps since 2.9 * 2.9 = 8.41