Спростити вираз:
1) (x-1)²+x(x-2)
2) (x+y)²-3xy
3) 15a+(-a+5)²
4) (x+2)²-x(x-1)

1) (x- 1)² + x(x - 2) = x² - 2x + 1 +x² - 2x = 2x² - 4x + 1

2) (x + y)² - 3xy = x² + 2xy + y² - 3xy = x² - xy + y²

3) 15a + (- a + 5)² = 15a + (5 - a)² = 15a + 25 - 10a + a² = a² + 5a + 25

4) (x + 2)² - x(x- 1) = x² + 4x + 4 - x² + x = 5x + 4