Question 26·Medium·Linear Equations in One Variable
Which value of satisfies the equation
For linear equations with fractions, first use the distributive property to remove parentheses and then combine like terms. To make calculations faster and less error-prone, you can also multiply the entire equation by the least common multiple of the denominators (here, 4) to clear fractions in one step. After that, move all variable terms to one side, constants to the other, and solve the resulting one-step equation, checking that your solution matches one of the answer choices.
Hints
Clear the parentheses first
Start by distributing over and over so that there are no parentheses in the equation.
Combine like terms on each side
After distributing, simplify each side by combining the constant numbers together and rewriting the equation in the form "(coefficient) + constant = (coefficient) + constant."
Move all k-terms to one side
Subtract one of the -terms from both sides so that all the 's are on one side and all the constants are on the other, then solve the resulting simple equation.
Be careful with fraction subtraction
When you subtract from , rewrite the fractions with a common denominator before subtracting the numerators.
Desmos Guide
Enter each side of the equation as a separate function
In Desmos, type y1 = (3/4)(x - 8) + 5 on one line and y2 = (1/2)(x + 4) + 9 on the next line. These represent the left and right sides of the equation as functions of .
Find the intersection point
Look for the point where the two graphs intersect. You can tap/click the intersection point; Desmos will display its coordinates .
Read off the value of k
The -coordinate of the intersection is the value of that makes both sides of the original equation equal. Match this -value to the correct answer choice.
Step-by-step Explanation
Distribute the fractions and simplify each side
Apply the distributive property to remove the parentheses.
-
Left side:
- So the left side becomes , which simplifies to .
-
Right side:
- So the right side becomes , which simplifies to .
Now the equation is:
Collect the variable terms on one side
Subtract from both sides to keep all terms together:
Compute the coefficient of by subtracting the fractions:
So the equation becomes:
Solve the one-step equation for k
First, isolate the term with by adding 1 to both sides:
Now, multiply both sides by 4 to solve for :
So the value of that satisfies the equation is , which corresponds to answer choice D.