To determine the correct equation corresponding to the measures of the angles, we need to go over the definition of complementary angles. Complementary angles are two angles whose measures add up to 90°.
Given that the angles are \(3x^\circ\) and \((4x + 1)^\circ\), we need to set up the equation as follows:
\[ 3x + (4x + 1) = 90 \]
Simplifying the left side, we combine like terms:
\[ 3x + 4x + 1 = 90 \] \[ 7x + 1 = 90 \]
So, the simplified equation is:
\[ (7x + 1)^\circ = 90^\circ \]
Thus, the correct response is:
\((7x + 1)^\circ = 90^\circ\)