Question 56·Medium·Linear Equations in One Variable
If , what is the value of ?
When you see the same expression (like ) repeated on both sides of an equation, treat that expression as a single variable to simplify your work. Rewrite the equation in terms of this new variable, isolate it with standard linear steps (get all variable terms on one side, constants on the other, then add/subtract/multiply/divide as needed), and finally translate back to the original expression the question asks about—often you never need to solve for the original variable itself, which saves time and reduces errors.
Hints
Focus on the repeated group
Notice that the expression appears inside parentheses on both sides of the equation. It can help to think of as a single variable, like .
Turn it into a simple linear equation
If you let , rewrite the equation in terms of only. Then use standard steps for solving a one-variable linear equation: get all terms on one side and constants on the other.
Answer exactly what is asked
After solving for your new variable, remember that it represents . You do not need to find itself; the value of that expression is what the question wants.
Desmos Guide
Graph both sides as functions
In Desmos, let stand for . Enter y1 = 6x - 5 on one line and y2 = 5x + 6 on another line to graph both sides of the equation.
Find the intersection
Look for the point where the two lines intersect and tap/click that point. The -coordinate of the intersection is the value of , which matches the correct answer choice.
Step-by-step Explanation
Rewrite the equation using a simpler variable
Start with the equation:
Notice that appears on both sides. Let to make the equation easier to see. Then the equation becomes:
Isolate the variable term
Now solve the linear equation .
First, subtract from both sides to get all the terms on one side:
You now have a simpler equation: .
Solve for the expression and answer the question
From , add 5 to both sides:
Remember that , so . The correct answer is 11.