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## Solving rational equations

Current time:0:00Total duration:3:11

# Equations with one rational expression

CCSS Math: HSA.REI.A.2

## Video transcript

So we have 14x plus 4
over negative 3x minus 2 is equal to 8. And I'll give you a
few moments to see if you can tackle
it on your own. So this equation
right here, at first it doesn't look like a
straightforward linear equation. We have one expression on
top of another expression. But as we'll see,
we can simplify this to turn it into
a linear equation. So the first thing
that I want to do is, I don't like this negative
3x plus 2 sitting here in the denominator,
it makes me stressed. So I want to multiply both
sides of this equation times negative 3x minus 2. What does that do for us? Well, on the left-hand side, you
have this negative 3x minus 2, it's going to be over
negative 3x minus 2, they will cancel out. And so you're left with,
on the left-hand side, your 14x plus 4. And on your right-hand
side, you just have to multiply 8 times
negative 3x minus 2. So you are left with--
well, 8 times negative 3x is negative 24x, and
then 8 times negative 2 is negative 16. And there you have it. We have simplified this to just
a traditional linear equation. We've got variables
on both sides, so we can just keep simplifying. So the first thing
I want to do, let's just say we want to
put all of our x terms on the left-hand side. So I want to get rid of this
negative 24x right over here. So the best way to
do that, I'm going to add 24x to the
right-hand side. I can't just do it to
the right-hand side, I have to also do it
to the left-hand side. And so I am left with,
on the left-hand side, 14x plus 24x is 38x. And then I have the plus
4-- Is equal to, well, negative 24x plus 24x. Those cancel each
other out, and we are left with just
the negative 16. Now we just have to
get rid of this 4 here. Let's subtract that
4 from both sides. And we are left with-- and
this is the home stretch now-- we are left with 38x is
equal to negative 16 minus 4 is negative 20. And so we can divide both
sides of this equation by 38. And we are left with x
is equal to negative 20 over 38, which can be
simplified further. Both the numerator the
denominator is divisible by 2. So let's divide the numerator
and denominator by 2, and we get negative 10 over 19. x is equal to negative 10
over 19, and we are done. I encourage you to
validate this for yourself. It's a little bit of a hairy
number right over here, but to take this number,
substitute it back into our original equation,
and validate that it actually does satisfy that equation.