Solving Algebraic Expressions: Confused with One Step | Need Help

[vande060]

Homework Statement

this is a step I ran across in a Doppler effect problem, it might be late but I just don't know why I am stumped here

there are two different, routes I can take with this problem and they both give me expressions I don't know how to solve. I would like to know how to solve them both, so I will post both. thank you for your time

1.052 = (1-x/340)/(1 + x/340)

and

200 = [4000/(1-x/340)] - [4000/(1+x/340)]

Homework Equations

none

The Attempt at a Solution

ive done the rest of the problem, just don't get this step. is it a quadratic maybe?

 

[eumyang]

So is the 1st one this?
$$1.052 = \frac{1-x/340}{1 + x/340}$$

If so, multiply both sides by the denominator, then multiply both sides by 340. You should then have a linear equation with no fractions.

For the 2nd, please double check your typing. Does the 1st 4000 have a slash afterward and the 2nd 4000 doesn't?

 

[vande060]

So is the 1st one this?
$$1.052 = \frac{1-x/340}{1 + x/340}$$

If so, multiply both sides by the denominator, then multiply both sides by 340. You should then have a linear equation with no fractions.

For the 2nd, please double check your typing. Does the 1st 4000 have a slash afterward and the 2nd 4000 doesn't?

second one should too sorry, i will edit now

1.052 + 1.052x/340 = 1-x/340

357.68 + 1.052x = 340 - x

x = -8.615 right?

 

[eumyang]

second one should too sorry, i will edit now

1.052 + 1.052x/340 = 1-x/340

357.68 + 1.052x = 340 - x

x = -8.615 right?

Well, my rounded answer was -8.616, but that assumes that 1.052 is not rounded.

So, does the 2nd one look like this?
$$200 = \frac{4000}{1-x/340} - \frac{4000}{1+x/340}$$

If so, I would start by multiplying each fraction by 340/340. Then multiply both sides of the equation by the LCD of the two denominators.