Question 113·Medium·Linear Equations in One Variable
If , what is the value of ?
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.