We have the expression:

When we have rational functions, where the denominator is a function of x, we have a restriction for the domain for any value of x that makes the denominator equal to 0.
That is because if the denominator is 0, then we have a function f(x) that is a division by zero and is undefined.
If we have a value that makes f(x) to be undefined, then this value of x does not belong to the domain of f(x).
Expression:

Answer: There is no restriction for x in the expression.
Answer:
4.68
Step-by-step explanation:
Remember to line up the decimal point. Subtract as ordinarily.
8.31
-3.43
--------
4.68
4.68 is your answer
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Answer:
Step-by-step explanation:
5(2x+3) = 85
10x + 15 = 85
x = (85 - 15)/10
x = 7