Practicing Success
If a2 + b2 = 4b + 6a - 13 find (a+b)2 - 10. |
10 15 20 25 |
15 |
a2 + b2 = 4b + 6a - 13 = 0 a2 - 6a + b2 - 4b + 13 = 0 a2 - 6a + 9 + b2 - 4b + 4 = 0 (a - 3)2 + (b - 2)2 = 0 ⇒ a = 3 and b = 2 Now ⇒ (a + b)2 - 10 = (3 + 2)2 - 10 = 15 |