To solve for \( x \) given that \( m∠5 = 112° \) and \( m∠8 = (2x + 8)° \), we need to determine the relationship between these angles. Assuming that angles 5 and 8 are supplementary (their measures add to 180°), we can write the equation as follows:
\[ m∠5 + m∠8 = 180° \]
Substituting the given values, we have:
\[ 112° + (2x + 8)° = 180° \]
Now, to simplify this equation, you can combine the constant terms:
\[ 112 + 8 + 2x = 180 \]
This simplifies to:
\[ 120 + 2x = 180 \]
Hence, the equation that will solve for \( x \) is:
\[ 2x + 120° = 180° \]
So, in the form \( ___x° + ___° = ___° \), it would be:
\[ 2x° + 120° = 180° \]