1. An algebraic expression of the form a + bx has the value of 15 when x = 2 and the value of 3 when x = 5. Calculate a + b.
2. compute \(123456789^2 - 2\cdot123456789\cdot 123456787 + 123456787^2 \)
3. Let \(r\) and \(s\) be the roots of \(3x^2 + 4x + 12 = 0\) . Find \(r^2 + s^2.\)
