Solve the system using substitution.
x+y=8
y=3x

a. (4,12)
b. (2,6)
c. (1/2,3/2)
d. (-4,-12)

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