whenever a number is inside an open parentheses like ( ), and there is another number attached to it immediately, then the number attached to the parentheses is used to multiply the number inside the parentheses.
For example,
3(7) means 3 x 7 = 21
4(-5) means 4 x -5 = -20
-2(-10) means -2 x -10 = 20
-(-19) means -1 x -19 = 19
and so on.
For the question
2.3 x 2.3 + 42 - (-19) = 2.3 x 2.3 + 42 + 19
= 5.29 + 61
=66.29