Respuesta :
Answer:
x=-39
Step-by-step explanation:
-x=81-49
-x=39
x=-39
1. Start by isolating \( x \) on one side of the equation. To do this, subtract 42 from both sides:
\[ 42 - x - 42 = 81 - 42 \]
\[ -x = 39 \]
2. To solve for \( x \), multiply both sides by -1 to change the sign of the variable:
\[ (-1) \times (-x) = (-1) \times 39 \]
\[ x = -39 \]
So, the solution to the equation \( 42 - x = 81 \) is \( x = -39 \).