Praxis Core Academic Skills for Educators: Mathematics (5733)Algebra and FunctionsEasy
A technician is calibrating a sensor. The sensor's reading 'R' (in ohms) is a function of the temperature 'T' (in degrees Celsius). The relationship is given by R(T) = 0.5T + 20. What is the temperature when the sensor reading is 45 ohms?
- A130 °C
- B25 °C
- C12.5 °C
- D50 °C
Show answer & explanationAnswer & explanation
Correct answer: D. 50 °C
To find the temperature when the sensor reading is 45 ohms, we set R(T) equal to 45 and solve the resulting linear equation for T.
Why the other options are wrong
- A. This would be the result of 0.5 * 45 + 20, which is evaluating R(45) instead of solving for T.
- B. This is the result of 45 - 20 = 25, forgetting to divide by 0.5 (or multiply by 2).
- C. This would be 45 - 20 = 25, then 25 / 2 = 12.5, if the operation was 2T + 20.
Solving Linear Equations
Solving a linear equation involves isolating the variable by performing inverse operations on both sides of the equation.
- Use addition/subtraction to move constant terms.
- Use multiplication/division to isolate the variable.
- Maintain equality by doing the same operation on both sides.
Memory trick: Balance the Equation, Target the Variable.