Algebra in physics equation?

Question

how do I solve this for X2?

1.34m/s = (6440m + X2) / (2402s + X2 / -0.447m/s)

Answer 1

Multiply both sides by the denominator, expand, and collect terms.

Answer 2

more explicitly

1.34m/s = (6440m + X2) / (2402s + X2 / -0.447m/s)

multiply both sides by (2402s + X2 / -0.447m/s)

(2402s + X2 / -0.447m/s) * 1.34 = (2402s + X2 / -0.447m/s) *  (6440m + X2) / (2402s + X2 / -0.447m/s)

the '(2402s + X2 / -0.447m/s)' then 'cancels out' on the right (assuming it isn't zero), leaving

1.34 * (2402s + X2 / -0.447m/s) = 6440m + X2

then distribute the 1.34 to get

(1.34 * 2402) + (1.34 * X2 / -0.447) = 6440 + X2

note that 1.34 * X2 / -0.447 is the same as

(-1.34/0.447) * X2

About now, with a caluculator you can simplify all those numbers and you will have something that looks more like this

a + b * X2 = c + X2

which you then jigger around to get

a - c = X2 - b * X2

a - c = X2 * ( 1 - b )

X2 = (a-c) / (1-b)

which of course, will turn into an actual number once you plug in real values for a, b, and c

In theory, a responsible mathematician will then look at the final values and make sure that any time they 'divided both sides by the same thing' that it wasn't "zero"

but usually, if that had been the case, something would probably have gone horribly wrong sooner.