15х++10+35х+42

It seems like you have a mathematical expression that you want to simplify. The expression provided is:

15х + 10 + 35х + 42

Let's combine like terms. The like terms here are the ones with "x" (15x and 35x) and the constants (10 and 42).

Adding the terms with "x" we get:

15х + 35х = 50х

Now, let's add the constants:

10 + 42 = 52

Combine both results to get the simplified expression:

50х + 52

The original expression 15х + 10 + 35х + 42 simplifies to 50х + 52.