Question 113·Medium·Linear Equations in One Variable
If , what is the value of ?
(Express the answer as an integer)
For linear equations with parentheses, first use the distributive property carefully to remove all parentheses, then combine like terms on each side to simplify. Next, move all x-terms to one side and all constants to the other using addition or subtraction, and finally divide to solve for x. Work step by step, writing each transformation on a new line to avoid small sign or distribution errors, and use a quick substitution check at the end if time allows.
Hints
Clear the parentheses first
Look at and . How can you use the distributive property to rewrite each expression without parentheses?
Simplify each side separately
After distributing, combine like terms (the x-terms together and the constants together) on each side before trying to solve the equation.
Collect x-terms on one side
Once each side is simplified, move all the x-terms to one side of the equation and all the constant numbers to the other side. What operation will undo an extra x-term or constant?
Desmos Guide
Graph each side of the equation
In Desmos, enter the left side as y = 4(2x + 5) - 3x and the right side as y = 7(x - 2) + 10. You will see two lines on the graph.
Find the intersection point
Tap or click on the point where the two lines intersect. The x-coordinate of this intersection is the solution to the equation .
Step-by-step Explanation
Distribute on both sides
Start by removing the parentheses using the distributive property.
- Left side:
- Distribute : and , so this becomes .
- Right side:
- Distribute : and , so this becomes .
Combine like terms on each side
Now simplify each side by combining like terms.
- Left side:
- Combine and to get , so the left side is .
- Right side:
- Combine and to get , so the right side is .
Now the equation is:
Get x-terms on one side and constants on the other
Move all the x-terms to one side and the constant terms to the other.
- Subtract from both sides:
- Now add to both sides to move constants away from the x-term:
Solve for x and check
Now isolate by dividing both sides by :
So the value of is . You can check by substituting back into the original equation to confirm both sides are equal.