3. 5 4i 5 4i 4 i + = + ⋅ + 4 − 4 4 i i − + i = 20 5i 16i + + + Concept and Vocabulary Check 2.1 4i 2 16 4i 4i + − − 1. ; i2 1 1 20 21i 4 = + − 16 +1 16 21i = + 2. complex; imaginary; real 17 16 21 3. 6i = + i ; 10 10i2 −27 + −48 = 14i 48 4. 27 ; 12i ; 15i i + 4. a. 16 i ⋅ 9 3 ⋅ 3 5. 18 ; i = i + 17 17 3i = 6. 2  9i 7i = 3 4i 3 + 3 7. 2  5i b. (−2 (−2 + −3)2 = + 3)2 i 2i 5 (−2)2 2(−2)(i = + 8. 3)2 i; 3) (i + i; 4 4i = − 4 4i = − 1 4i = − 3 3i2 + 3 3(−1) + 3 9. 6 1  i 2
3. 5 + 4i = 5 + 4i ⋅ 4 + i 4 − i 4 − i 4 + i 20 + 5i + 16i + 4i 2 = Concept and Vocabulary Check 2.1 16 + 4i − 4i − i2 = 20 + 21i − 4 1. 1 ; 1 16 +1 = 16 + 21i 2. complex; imaginary; real 17 = 16 + 21 i 3. 6i 4. a. 17 17 −27 + −48 = i = i 27 + i 9 ⋅ 3 + i 48 16 ⋅ 3 4. 14i 5. 18 ; 15i ; 12i ; 10i2 ; 10 = 3i = 7i 3 + 4i 3 3 6. 2  9i 7. 2  5i b. (−2 + −3)2 = (−2 + i 3)2 = (−2)2 + 2(−2)(i 3) + (i 3)2 8. i; i; 2i 5 = 4 − 4i = 4 − 4i = 1 − 4i 3 + 3i2 3 + 3(−1) 3 9. 1  i 6 2