Register to reply

How do I solve an equation with a variable in the numerator?

by AVReidy
Tags: equation, numerator, solve, variable
Share this thread:
AVReidy
#1
Sep13-11, 02:29 PM
P: 49
1. The problem statement, all variables and given/known data

I just missed a 16-point question on a quiz because I didn't know how to separate the variable. It was an absolute value equation, but I just need to know how to deal with a variable in a fraction. Here's what it looked like:

2. Relevant equations

(5x+10)/2 = 20

3. The attempt at a solution
I tried multiplying everything by the denominator, but I'm not sure if or why that works. Any help would be greatly appreciated, thanks!
Phys.Org News Partner Science news on Phys.org
New type of solar concentrator desn't block the view
Researchers demonstrate ultra low-field nuclear magnetic resonance using Earth's magnetic field
Asian inventions dominate energy storage systems
Borek
#2
Sep13-11, 02:32 PM
Admin
Borek's Avatar
P: 23,530
Multiplying by denominator should work. You can do anything that doesn't change the equality - that means adding, subtracting, multiplying or dividing both sides of the equation by the same thing.

Or you could write the fraction as [itex]\frac {5x}{2} + \frac {10}{2}[/itex].
AVReidy
#3
Sep13-11, 04:02 PM
P: 49
Thanks!

J2R
#4
Sep16-11, 01:33 AM
P: 2
How do I solve an equation with a variable in the numerator?

The easiest way is to multiply both sides of the equation by the denominator. The reason why this works is because it doesn't change the equality.

(5x+10)/2 = 20
5x+10 = 40
5x = 30
x = 6

Even if the variable was in the denominator, you can still solve for the variable using the same steps.

2/(5x+10) = 20
2 = 100x + 200
-198 = 100x
-198/100 = x
x = -99/50


Register to reply

Related Discussions
How do I solve an equation with a fraction as the variable's coefficient? Precalculus Mathematics Homework 6
Non-linear ODE: Use change of variable to solve the equation for initial conditions Calculus & Beyond Homework 1
Double variable equation- how to solve? Precalculus Mathematics Homework 6
How do you solve an equation with the variable in the denominator Calculus & Beyond Homework 1
Solve for the variable? Precalculus Mathematics Homework 3