1) (x + 2)²
2) (y - 5)²
1) x² + 4x + 4
2) y² - 10y + 25
1) (x + 2)² = x² + 2*2*x + 2² = x² + 4x + 4
2) (y - 5)² = y² - 2*5*y + 5² = y² - 10y + 25
1) x² - 9
2) 4a² - b²
1) (x - 3)(x + 3)
2) (2a - b)(2a + b)
1) x² - 9 = x² - 3² = (x - 3)(x + 3)
2) 4a² - b² = (2a)² - b² = (2a - b)(2a + b)
1) 2x + 5 = 13
2) 3y - 7 = 8
1) x = 4
2) y = 5
1) 2x + 5 = 13 ⇒ 2x = 13 - 5 ⇒ 2x = 8 ⇒ x = 4
2) 3y - 7 = 8 ⇒ 3y = 8 + 7 ⇒ 3y = 15 ⇒ y = 5