The given expression can be rewritten an infinite number of ways. Here are a couple of them
.. 10x -15
.. -50(-0.2x +0.3)
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You need some additional condition before you can talk about solutions. Perhaps "= 0", as in 5(2x -3) = 0, then x=3/2 is the one solution.
It looks like there might be a missing operator between 5 and (. That would be an additional piece of information needed before the number of solutions can be given.