What step do you take to solve the following equation: X - 7 = -1* ADD '-1 to both sides
ADD '7' to both sides
ADD 'X' to both sides
SUBTRACT -1' from both sides
SUBTRACT '8' from both sides

1. ∠1 is complementary to ∠2 and ∠3 is complementary to ∠2. subtraction property of equality 2. m∠1 + m∠2 = 90 and m∠3 + m∠2 = 90 substitution 3. m∠1 + m∠2 = m∠3 + m∠2 definition of complementary 4. m∠1 = m∠3 given