Question 170·Medium·Nonlinear Equations in One Variable; Systems in Two Variables
What is the solution to the equation above?
For rational equations where the denominators are the same or share a simple factor, first note any excluded values that make a denominator zero. Then multiply both sides by the least common denominator to clear all fractions, turning the problem into a linear (or sometimes quadratic) equation. Carefully distribute and combine like terms, watch negative signs when moving terms across the equals sign, and finally check that your solution does not make any original denominator zero.
Hints
Look at the denominator
Both fractions have the denominator . What value of would make this denominator zero, and why can that value never be a solution?
Eliminate the fractions
Try multiplying both sides of the equation by . Make sure you multiply every term on both sides by , not just the fractions.
Simplify to a linear equation
After multiplying by , you should no longer have any denominators. Simplify the right-hand side to get an equation of the form , then solve for .
Desmos Guide
Graph both sides of the equation
In Desmos, enter the left side as y = (5x+7)/(x-2) and the right side as y = 3 + 1/(x-2) in two separate lines.
Find the intersection point
Look for the point where the two graphs intersect. Tap or click on the intersection to see its coordinates.
Read off the solution
The -coordinate of the intersection is the solution to the equation (as long as it is not , which would make the denominator zero). Use that -value as your answer.
Step-by-step Explanation
Identify the restriction on x
The denominator cannot be zero, so . Any solution we find must not be .
Clear the fractions by multiplying by the denominator
Multiply both sides of the equation by (which is allowed because ):
The left side simplifies to . On the right side, distribute :
Simplify and form a linear equation
Simplify the expression on the right side:
so the equation becomes
which simplifies to
Now you have a linear equation in .
Solve the linear equation and check the solution
Solve :
- Subtract from both sides: .
- Subtract from both sides: .
- Divide both sides by : .
Check that this does not violate the restriction (it does not), and it satisfies the original equation, so the solution is .