1) f(x) = (x+3)² + (2x-1)(x+3)
f(x) = (x+3)(x+3) + (2x-1)(x+3)
f(x) = x² + 3x + 3x + 9 +2x² + 6x - x - 3
f(x) = 3x² + 11x + 6
2)
f(x) = (x+3)² + (2x-1)(x+3)
f(x) = (x+3) (x+3 + 2x -1)
f(x) = (x+3) ( 3x +2)
3)
f(√2) = (√2+3) (3√2+2)
f(√2) = 6 + 2√2 + 9√2 + 6
f(√2) = 11√2 + 12