Question 55·Easy·Nonlinear Equations in One Variable; Systems in Two Variables
Given the equation
which value is a solution to the equation?
For absolute value equations of the form , quickly rewrite them as two linear equations, and , and solve both. Then compare the resulting -values to the answer choices, and optionally plug candidates back into the original absolute value expression to confirm they satisfy the equation.
Hints
Think about what absolute value means
If , what two possible values can have? Rewrite without the absolute value bars using this idea.
Split into two simpler equations
Set up two equations: one where equals a positive number, and one where equals the corresponding negative number. Then solve each equation for .
Use the answer choices as a check
After you find the possible values of , compare them to the answer choices. You can also plug each choice into to see which one makes the equation true.
Desmos Guide
Graph both sides of the equation
In Desmos, type y = |2x - 7| on one line and y = 3 on another line so you can see where the graphs intersect.
Find the intersection x-values
Click on the points where the V-shaped graph of meets the horizontal line . Note the -coordinates of these intersection points, and then see which of the answer choices matches one of those -values.
Step-by-step Explanation
Use the definition of absolute value
The equation is
By definition, means or . Here, is , so we write two equations:
- .
Begin solving the two linear equations
Solve each equation setup separately:
For :
For :
These lead to two values of ; we will identify the matching choice next.
Compare the solutions to the answer choices
From and , we find and . The answer choices are , , , and . Among these, only is listed.
Therefore, the correct answer is 2.